Pelvic floor dilation for reducing injury and intervention arising from labor

Abstract

Methods and devices therapeutically dilate the pelvic floor of a nulliparous patient and thereby to reduce trauma and injury to patient tissue and to the neonate during labor and delivery. The methods and devices reduce the rate of ani muscle avulsion, reduce the occurrence of Cesarean procedures and reduce brachial plexus injury to the neonate. The methods and devices, in one practice, dispose an intrapartum electromechanical pelvic floor dilator into the vaginal canal and across the pelvic floor of the patient, and therapeutically expand the birth canal to pre-acclimate the tissue of the patient that is involved later stages of labor and delivery and thereby reduce injury.

Description

PELVIC FLOOR DILATION FOR REDUCING INJURYAND INTERVENTION ARISING FROM LABORFIELD OF THE INVENTION

[0001] The field is labor and delivery and more particularly, improved devices and methods for addressing tissue damage and intervention during labor and delivery.BACKGROUND OF THE INVENTION

[0002] Approximately 134 million women give birth worldwide each year, of whom 3.0 million give birth vaginally in the United States.

[0003] Birth most commonly happens through the process of labor and delivery. Labor is the physiologic process by which a mother pushes the fetus from the uterus to the outside world. Labor is characterized by regular, painful contractions with change in cervical dilation and effacement. The contractions drive the fetus through the birth canal, which includes the cervix and the vaginal canal. The birth canal provides a passage for the fetus through the pelvic floor of the mother.

[0004] The pelvic floor is an important and complex connection of muscles, ligaments and bone structure which act as a support for the pelvic organs such as the bladder, the rectum, intestines and urethra. As such, the passage of the fetus from the uterus to the outside world requires a passage through the dense complex of muscles of the pelvic floor. The passing of the fetus may adversely affect the health of this complex of muscle that is critical to daily activities.

[0005] Although there is a known link between labor and delivery and pelvic floor disorders, the exact physiologic mechanisms that lead to many of these disorders remain under investigation. It is thought that damage to the pelvic floor musculature during childbirth may be one of the most significant causes of pelvic floor disorders. Babies can be relatively big, with large heads and broad shoulders, as compared to the diameter of the birth canal. This, as is generally known, can lead to injury of the mother, and in particular to the pelvic floor of the mother, as the mother pushes the baby through the birth canal so fetal descent takes place. Complicated descent of the neonate can also lead to emergencyintervention, often surgical delivery to aid the mother and reduce risk of injury to the descending neonate.

[0006] During vaginal delivery, labor and delivery are clinically divided into three stages. The first stage begins with cervical effacement and is completed with full cervical dilation that will allow the passage of the fetus through the birth canal. The second stage is defined by the passage of the fetus through the birth canal. During the second stage the fetus descends as it moves and rotates to overcome the resistance presented by the maternal bony pelvis and the soft tissue of the pelvic floor. The second stage ends with the delivery of the fetus. The third stage is comprised of the separation and expulsion of the placenta.

[0007] As the fetal body descends into the birth canal during the second stage, it exerts direct pressure on the pelvic floor. The fetus passes through the birth canal by stretching the fibers of the levator ani muscle and connective tissues, drastically distending and often damaging the pelvic floor musculature. Unlike the gradual dilation of the cervix during the first stage of labor, the pelvic floor and vaginal canal must dilate rapidly during the second phase of labor. The introitus, or opening of the vagina, for the average woman, has a baseline resting diameter of roughly 2.6 cm. During the first phase of labor, while the cervix is dilating, the vagina stays at this baseline diameter, but when the baby passes through the cervix the vaginal canal dilates from 2.6 cm up to 10 cm, the average head diameter of a newborn baby. This 3.8X expansion in diameter and approximately 15X expansion in area occurs in a matter of seconds to minutes.

[0008] Studies show that 15-35% of labor processes suffer damage to their pelvic floor muscles, where the mother’s muscles are tom from the pelvic bone or over-stretched to the point where they become functionally impaired. The tearing of the muscle from the supporting bone, termed an avulsion, is a significant injury and complete, or full, avulsions are strongly associated with the development of pelvic organ prolapse later in life. Repairing these injuries is invasive and the repair procedures can also be ineffective.

[0009] In some cases, traditional vaginal delivery is not feasible and the physician must intervene. The most common surgical intervention is a cesarean birth also known as a C- section. This is a surgical delivery method where the baby is delivered through an incision made by the surgeon and located in the mother's abdomen and uterus. Although Caesarean sections can be planned in advance, they also occur as an emergency intervention when traditional vaginal delivery is failing. Although cesarean birth is successful and generally safe, it is substantial surgical procedure with concomitant recovery time, pain, and trauma.

[0010] One system for reducing trauma during vaginal delivery is disclosed in US Patent 9,492,197 issued to the assignee hereof. Such systems can reduce tissue damage and injury to the patient. Although such systems can work well, there remains a need to make use of such systems facile for patients and clinicians. Systems that are more facile to use allow more women to be treated as labor and delivery is carried out under a broad range of clinical situations, some of which take place without physician level clinicians. Still further there is a need for systems and methods that provide improved tissue preparation to address the burden of labor and risk of injury to the laboring patient and the infant.

[0011] SUMMARY OF THE INVENTION

[0012] The methods and devices described herein therapeutically dilate the pelvic floor of a patient during labor and thereby reduce trauma and injury to tissue during labor and delivery. The methods and devices described herein can therapeutically pre-acclimate the patient while the patient is in labor, and treat the tissue involved in the labor process. The therapeutic effect of such treatment can reduce injury to the delivering patient, reduce the need for cesarean intervention and reduce injury to the neonate. As disclosed herein, such methods and devices reduce the rate of ani muscle avulsion and in particular reduce the occurrence of complete levator ani muscle (LAM) avulsions. This reduction in full LAM avulsions reduces an injury associated with serious sequelae including pelvic organ prolapse. The methods and devices described herein reduce the occurrence of cesarean procedures, particularly cesarean procedures arising from second stage arrest. Further, and surprisingly the methods and devices described herein reduce infant brachial plexus injury.

[0013] In certain embodiments, the devices described herein provide a facile to use and processor controlled intrapartum pelvic floor dilator with an integrated electromechanical dilator that expands diametrically in a therapeutic method that acclimates, inter alia, the tissue about levator ani muscle complex over a period of thirty to ninety minutes, and more typically around sixty minutes. This acclimation reduces the occurrence of full LAM avulsion, reduces the occurrence of second stage arrest cesarean section and reduces the occurrence of brachial plexus injury to the neonate.

[0014] In one embodiment, the methods described herein provide a method for reducing full levator ani muscle (LAM) avulsion during vaginal delivery in a nulliparous patient. Such method may identify a time during stage one of labor for inserting an intrapartum pelvic floor dilator into the patient. The clinician inserts the intrapartum pelvic floor dilator within the vagina of the patient. Once inserted, for a period of time that is usefulto achieve the therapeutic effect, typically between 30 minutes and 90 minutes, the intrapartum pelvic floor dilator automatically expands to pre-acclimate the vaginal canal and surrounding pelvic tissue of the patient. Typically, the expansion involves expanding the vaginal canal and pelvic tissue from a resting diameter of about 3 cm to a resting diameter of about 1 to 2 cm smaller than the average fetal biparietal diameter. The device is then removed and removal is typically prior to descent of the neonate past the cervix. Removal will have the clinician remove the intrapartum pelvic floor dilator from the vagina of the patient. Typically, removal is done prior to full cervical dilation of the patient.

[0015] Optionally, the method identifies the time during stage one of labor for insertion of the intrapartum pelvic floor dilator by identifying a time when cervical dilation has reached about 6 cm.

[0016] In one embodiment, automatically expanding the intrapartum pelvic floor dilator includes providing within the intrapartum pelvic floor dilator an electric motor and a processor configured to operate the electric motor to electromechanically, and under control of the processor, expand a diameter of the intrapartum pelvic floor dilator. The processor may be configured to expand the intrapartum pelvic floor dilator by incrementally expanding the diameter of the intrapartum pelvic floor dilator by a preselected increment. Further, the processor may be configured so that the method expands the intrapartum pelvic floor dilator by sequentially increasing the diameter of the intrapartum pelvic floor diameter by preselected increments of time to achieve a substantially linear rate of expansion.

[0017] Further, the intrapartum pelvic floor dilator may include an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the intrapartum pelvic floor dilator.

[0018] Typically, the method will measure a force applied by the expanding intrapartum pelvic floor dilator to a vaginal wall or a pelvic floor of the patient and continuously comparing the measured force to a safety threshold. By measuring such force the method may compare the measured force to the safety threshold, typically a value that represents, a safe force to apply to the patient. Further, the method may be carried out so that expanding the diameter of the intrapartum pelvic floor dilator at an expansion rate below a pre-set safety threshold rate of expansion.

[0019] The method may be repeated if the patient does not enter a later stage of labor, typically the second stage, within some time period, such as three or four hours, from the first therapeutic expansive treatment. This may address the effect that elasticity of the tissue returns to a state comparable to the state it was in prior to the expansive preacclimationprocess. As such, the methods herein may include measuring an elapsed time since removing the intrapartum pelvic floor dilator and reinserting the intrapartum pelvic floor dilator and repeating the method for reducing full levator ani muscle if the measured elapsed time from removing the intrapartum pelvic floor dilator is more than three hours.

[0020] Insertion will typically be placement of the device by a treating clinician, often a physician, and typically inserting the intrapartum pelvic floor dilator includes having the intrapartum pelvic floor dilator transverse at least part of the pubic bone and at least part of the pelvic floor and having the intrapartum pelvic floor dilator engaged to the lower birth canal proximate the urethra, across the perineal body and levator ani muscles and maintained distal from the cervix. Optionally, the method further includes administering an epidural.

[0021] In some practices of the methods described herein, the method may include providing the intrapartum pelvic floor dilator with a user interface integrated into the intrapartum pelvic floor dilator and being capable of indicating the current diameter of the intrapartum pelvic floor dilator. This allows a treating clinician to set the intrapartum pelvic floor dilator (IPD) for operative therapeutic expansion under the control of the processor that is configured to carry out the therapeutic expansive treatment. The user interface can include controls that allow the IPD to control the start of expansion, to control stopping the expansion and to control the retraction of the diameter of the IPD, including for removal from the patient.

[0022] The methods described herein further include methods for reducing an occurrence of second stage arrest cesarean section delivery in a nulliparous patient. Such methods may include inserting an intrapartum pelvic floor dilator within the vagina of the patient and for a period of time of between 30 minutes and 90 minutes, expanding the intrapartum pelvic floor dilator during labor to pre-acclimate the patient by expanding the intrapartum pelvic dilator from a diameter of about 3.0 cm to a diameter of about at least 6.0 cm. The method includes removing the intrapartum pelvic floor dilator from the vagina of the patient. Optionally, the method includes, prior to inserting the intrapartum pelvic floor dilator, examining the patient and determining if the patient is at risk of needing an emergency cesarean section. Expanding the intrapartum pelvic floor device typically includes incrementally expanding the diameter of the intrapartum pelvic floor dilator by a preselected increment. Optionally, the method expands the intrapartum pelvic floor dilator by sequentially increasing the diameter of the intrapartum pelvic floor diameter at preselected increments of time to achieve a substantially linear rate of expansion. The method typically employs a force sensor to measure a force applied by the expanding intrapartum pelvic floordilator to a vaginal wall or pelvic floor of the patient and comparing the measured force to a safety threshold. Expanding the diameter of the intrapartum pelvic floor dilator may be done at an expansion rate below a pre-set safety threshold rate of expansion.

[0023] In some practices, the method for reducing an occurrence of second stage arrest cesarean section delivery in a nulliparous patient expands the intrapartum pelvic floor dilator at least in part by providing within the intrapartum pelvic floor dilator an electric motor and a processor configured to operate the electric motor to electromechanically, and under control of the processor, expand a diameter of the intrapartum pelvic floor dilator. Optionally, the intrapartum pelvic floor dilator includes an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the dilator.

[0024] In one practice, the methods described herein provide methods for reducing an occurrence of brachial plexus injury to a neonate during delivery by a patient, by inserting an intrapartum pelvic floor dilator within the vagina of the patient, and for a period of time of between 30 minutes and 90 minutes, expanding the intrapartum pelvic floor dilator during labor to pre-acclimate the patient by expanding the intrapartum pelvic dilator from a diameter of about 3 cm to a diameter of about at least 6 cm, and removing the intrapartum pelvic floor dilator from the vagina of the patient. In this embodiment, expanding the intrapartum pelvic floor device may include incrementally expanding the diameter of the intrapartum pelvic floor dilator by a preselected increment. Further and optionally, expanding the intrapartum pelvic floor dilator includes sequentially increasing the diameter of the intrapartum pelvic floor diameter at preselected increments of time to achieve a substantially linear rate of expansion. Further, the methods for reducing an occurrence of brachial plexus injury to a neonate during delivery by a patient may measure a force applied by the expanding intrapartum pelvic floor dilator to a vaginal wall or pelvic floor of the patient and comparing the measured force to a safety threshold. In one embodiment the method for reducing an occurrence of brachial plexus injury to a neonate during delivery by a patient may include expanding the diameter of the intrapartum pelvic floor dilator at an expansion rate below a pre-set safety threshold rate of expansion.

[0025] In some embodiments of these methods for reducing an occurrence of brachial plexus injury to a neonate during delivery by a patient, the methods may include providing an intrapartum pelvic floor dilator that has within the intrapartum pelvic floor dilator an electric motor and a processor configured to operate the electric motor to electromechanically, and under control of the processor, expand a diameter of the intrapartum pelvic floor dilator.Optionally, the method may apply an intrapartum pelvic floor dilator that includes an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the intrapartum pelvic floor dilator.

[0026] In another aspect, the devices described herein may include apparatus for reducing injury during delivery of a neonate by a laboring nulliparous patient, and the apparatus may comprise a diameter expandable intrapartum pelvic floor dilator sized for intravaginal insertion into a nulliparous patient, a processor integrated within the intrapartum pelvic floor dilator and configured for expanding a diameter of the intrapartum pelvic floor dilator such that an initial diameter expansion fits the intrapartum pelvic floor dilator into engagement with the vaginal wall of the patient and secures the intrapartum pelvic floor dilator against dislodgement due to the type of movement that occurs during labor, and a therapeutic expansion that dilates the dilator in incremental steps selected to allow substantially even incremental expansion of the diameter over a time period selected to allow a controlled and radially directed force to therapeutically expand patient tissue involved in stage two of labor.

[0027] The apparatus optionally may include an intrapartum pelvic floor dilator that is formed as a cylinder having a collapsed configuration and an expanded configuration, the collapsed configuration having a cylindrical exterior outer wall with a long surface extending parallel to an interior axis of the cylinder and having a plurality of arc-shaped sections capable of expanding outward and radially from the interior axis to apply a radially directed force to the tissue of the patient, and an electric motor integrated into the intrapartum pelvic floor dilator and operating under control of the processor and that couples to a mechanical assembly to controllably move the arc-shaped sections radially outward from the interior axis.

[0028] Optionally, the apparatus may include an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the intrapartum pelvic floor dilator. Further optionally, the apparatus may include a user interface integrated into the intrapartum pelvic floor dilator and being capable of indicating the current diameter of the intrapartum pelvic floor dilator.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The foregoing and other objects and advantages of the systems and methods disclosed herein will be appreciated more fully from the following further description thereof, with reference to the accompanying drawings wherein;

[0030] Figs. 1A-1E illustrate one embodiment of an electromechanical intrapartum pelvic floor dilator useful in the methods described herein;

[0031] Figs. 2A and 2B illustrate the IPD of Figs. 1A-1E disposed in a patient in a collapsed configuration and an expanded configuration respectively;

[0032] Figs. 3 A and 3B depict curves of the increasing diameter over time and shows a substantially linear increase in diameter over a 30 minute time period of the treatment and a 60 minute time period of the treatment.

[0033] Fig. 4 depicts an intrapartum pelvic floor dilator of the type depicted in Figs. 1 A- 1E disposed on a model patient to illustrate one example treatment for therapeutically expanding the vaginal canal prior to descent of the neonate;

[0034] Fig. 5 depicts an intrapartum pelvic floor dilator superimposed over an image depicting the anatomy of a patient to illustrate one placement of the dilator during a therapeutic treatment;

[0035] Figs. 6A and 6B illustrate an uninjured and injured pelvic floor and the type of injury that the devices described herein reduce;

[0036] Figs. 7A and 7B depict the dilation device at the beginning of a treatment and toward the end of a treatment;

[0037] Fig. 8 depicts tomographic imaging of the clinical examples disclosed herein and including transperineal tomographic ultrasound images of the levator ani muscle and sequential-level ultrasound imaging revealing full left-sided avulsion (white arrows) of the levator ani pelvic floor muscle group three months after vaginal delivery. The avulsion injury appears as a frank interruption in the smooth arcing topography of the intact LAM complex seen on the contralateral (right) side in these ultrasound images;

[0038] Fig. 9 is a flowchart of the enrollment and study progression of treatment for full LAM avulsion, second stage arrest and brachial plexus injury,

[0039] Fig. 10 presents Table 1 of the clinical study showing participant demographics;

[0040] Fig. 11 presents Table 2 of the clinical study showing Labor and delivery characteristics;

[0041] Fig. 12 presents Table 3 of the clinical study showing three-month ultrasound results;

[0042] Fig. 13 presents Table 4 of the clinical study showing Adverse events (AEs); and

[0043] Fig. 14 presents Table 5 of the clinical study showing three-month patient- reported outcomes.DETAILED DESCRIPTION

[0044] The devices and methods described herein are intended to prepare and dilate vaginal tissue and perineal tissue during labor to reduce or prevent, among other things, pelvic floor damage, surgical intervention during labor and, injury to the neonate. In particular, the devices and methods described herein provide for therapeutically treating a mother during early stages of labor in preparation for the delivery phase of labor. Still further, disclosed herein are the therapeutic effects achieved by using an Intrapartum Pelvic Dilator (IPD) device to reduce levator ani muscle avulsion, the occurrence of second stage arrest and injury to the infant during primiparous vaginal delivery.

[0045] In particular, the inventors have shown, through inter alia clinical studies with over 200 nulliparous women, that the methods and devices described herein which, in one practice, dispose an intrapartum electromechanical pelvic floor dilator into the vaginal canal and across the pelvic floor of the patient, and therapeutically expand the birth canal, reduce full LAM avulsions and the likelihood of surgical intervention, such as cesarian procedures including cesarian procedures caused by second stage arrest. Moreover, these methods and devices reduce neonate brachial plexus injury.

[0046] It is understood that labor is a complex process. Each nulliparous women faces her first labor having to accept that the experiences of nulliparous women vary tremendously from women to women. Further, each delivery is different and there are many factors that occur and interact that can cause one women to a have a relatively conventional and problem free labor and delivery process and in contrast may cause another women to have a difficult and, in some cases injurious process. The inventors have found that expansive therapy proximate to stage two of labor and delivered by way of an expanding intrapartum pelvic floor dilator within the lower birth canal, can reduce the likelihood of injury, and in particular significantly reduce the likelihood of complete LAM avulsion, cesarian procedures caused by second stage arrest and neonate brachial plexus injury

[0047] More specifically, in one embodiment the methods described herein reduce full levator ani muscle (LAM) avulsion during vaginal delivery in a nulliparous patient.

[0048] In practice, the clinician identifies a time during stage one of labor for inserting an intrapartum pelvic floor dilator into the nulliparous patient. As this is an intrapartum procedure, the clinician is typically looking for a period of time during the first stage of labor, such that the patient is involved in the labor and delivery process and IPD therapy is timely. In one practice, the identification of the time to insert the IPD and begin the IPD therapy is based on a measure of cervical dilation. For example, it may be that the clinician will check the dilation of the patient’s cervix, measuring dilation using typicalclinical techniques. Once a cervical dilation of about 3 cm is detected, the intrapartum pelvic floor dilator is inserted into the patient and therapy can begin.

[0049] This measure of cervical dilation indicates that the patient is involved in the labor and delivery process and starting treatment at this time can achieve the targeted therapeutic benefit. Given that the treatment is to have the IPD slowly stretch the vagina and surrounding pelvic tissues during late first-stage labor, thereby pre-acclimating the LAM and other pelvic floor components to the strain of crowning, the time of starting the therapy should be sufficiently spaced in time from the commencement of neonate descent to allow for this slow stretching to occur. In one practice, the clinician will start the IPD therapy with more than one hour estimated to be remaining until complete cervical dilation. The measure of complete cervical dilation can be taken or estimated using any of the known techniques employed by clinicians during the labor and delivery process. As is generally known in the field, cervical dilation during labor and delivery is typically measured using a manual vaginal examination performed by the clinician or any healthcare provider assisting the patient. This manual technique involves inserting two gloved fingers into the vagina to assess the opening of the cervix, typically estimating its diameter in centimeters from 0.0 cm (completely closed) to 10.0 cm (fully dilated). Experienced practitioners rely on tactile perception and clinical experience to make this assessment. In some cases, ultrasound imaging, particularly transperineal or transvaginal ultrasound, may be used to provide a more objective measurement, especially when manual exams are difficult or inconclusive. Any suitable technique for measuring cervical dilation can be used and the technique employed will depend on the circumstances of the labor, characteristics of the patient and the neonate and the other factors that will be evaluated by the treating clinician.

[0050] The clinician inserts the intrapartum pelvic floor dilator within the vagina of the patient. Once inserted, for a period of time that is useful to achieve the therapeutic effect, typically between 30 minutes and 90 minutes, the intrapartum pelvic floor dilator automatically expands to pre-acclimate the vaginal canal and surrounding pelvic tissue of the patient. Typically, the expansion involves expanding the vaginal canal and pelvic tissue from a resting diameter of about 3.0 cm to a resting diameter of about 8.0 cm, or to about 1.0 to 2.0 cm smaller than the average fetal biparietal diameter. However, the end point for the therapy can, at least in part, be determined by the treating clinician. For example, in the clinical studies disclosed herein some patients were deemed fully treated once the dilation of the IPD had reached or was greater than about 6.7 cm. The end of the treatment may be once the clinician has found that the IPD has expanded slowly, and in one practice at a constant rate,thereby gently pre-stretching the vagina and surrounding pelvic muscles. The determination of the end point for the IPD therapy can be made any suitable way, including based on the diameter of the IPD, such as the IPD reaching a diameter of between 5.0 cm and 10.0 cm, or between 6.0 cm and 8.0 cm, or between 6.0 cm and 7.0 cm or any suitable range. Additionally, in other practices the tissue of the patient is digitally tested to check the elasticity of the tissue at the current expanded diameter and to determine whether the tissue has relaxed sufficiently at a sufficient dilation to provide for the therapeutic effect during the upcoming dilation caused by neonate descent.

[0051] Once the expanding stage of the therapy is complete, the IPD is removed. Removal is typically prior to the descent of the neonate past the cervix. Removal will have the clinician remove the IPD from the vagina of the patient. Typically, removal is done prior to full dilation of the patient.

[0052] Clinical Study Overview

[0053] A multi-center, randomized controlled trial was conducted with 214 nulliparous participants planning vaginal delivery. The study established the effectiveness of an intrapartum electromechanical pelvic floor dilator to reduce the risk of levator ani muscle (LAM) avulsion during vaginal delivery.

[0054] During the first stage of labor, participants were randomized to receive the intravaginal IPD device or standard-of-care labor management. The primary effectiveness endpoint was the presence of full LAM avulsion on transperineal pelvic-floor ultrasound at three (3) months. Three (3) urogynecologists performed blinded interpretation of ultrasound images. The primary safety endpoint was adverse events (AEs) through three months.

[0055] A total of 214 women were randomized to Device (n = 113) or Control (n = 101) groups / arms. Fig. 9 sets out the enrollment and study progression for this evaluation study. As seen from Fig. 9, of 113 Device assignees, 82 had a device placed, of whom 68 delivered vaginally. Of 101 Control participants, 85 delivered vaginally. At 3 months, 110 participants, 46 Device subjects who received full device treatment, and 64 Controls underwent ultrasound for the per-protocol analysis. No full LAM avulsions (0.0%) occurred in the Device group versus 7 out of 64 (10.9%) in the Control group (p = 0.040; two-tailed Fisher’s test). A single maternal serious AE (laceration) was device related; no neonate serious AEs were device related. Conclusions from this trial were that the pelvic floor dilator device and therapy significantly reduced the incidence of complete LAM avulsion in nulliparous individuals undergoing first vaginal childbirth. The dilator demonstrated an acceptable safety profile and was well received by recipients. The data shows that this IPDtherapy is effective for reducing the rate of complete LAM avulsion, therapeutically effective for reducing rates of Cesarean section due to arrest of stage two labor and therapeutically effective for reducing the occurrence of brachial plexus injury to the infant.

[0056] Example Embodiment

[0057] The methods and devices described herein in one example embodiment are intended to prepare and dilate vaginal tissue during labor to reduce or prevent, among other things, pelvic floor damage and later development of pelvic floor disorder.

[0058] In particular, the methods described herein provide for therapeutically treating a mother during early stages of labor in preparation for the delivery phase of labor. The disclosed methods can reduce pelvic floor injury to a patient during a labor and delivery procedure, and in one practice will insert intrapartum a pelvic floor dilator intravaginally of the patient. The method will then expand the pelvic floor dilator to dilate the vagina and surrounding pelvic tissue during the labor process and control the strain rate of the pelvic tissue during the labor process. In one practice the method expands the vaginal introitus and pelvic tissue from a resting diameter of about 3.0 cm to a resting diameter of about 6.7 cm to 8.0 cm over a period of time of about 60 minutes, and typically between 30 minutes and 90 minutes.

[0059] The treating physician or clinician can observe the patient and determine the involvement of the patient in the labor process and current cervical dilation and rate of dilation. Optionally, the methods may include some evaluation of likelihood of LAM avulsion, second stage arrest and brachial plexus injury, prior to initiating treatment.

[0060] In one practice, the physician / clinician inserts intrapartum the pelvic floor dilator by inserting the pelvic floor dilator during active stage one labor with more than one hour estimated remaining until cervical dilation is complete. Once in place, the physician or clinician may expand the dilator at a controlled rate below a pre-set safety threshold rate of expansion and at a constant rate to thereby gently pre-stretch the vagina and surrounding pelvic tissues. The pre-set safety threshold rate of expansion may be a rate of expansion, that is the rate over time by which the radial diameter of the pelvic floor dilator is expanded. For example, it may be that the pelvic floor dilator expands a pre-selected amount at each increment, such as a preselected increment in the range of .005 cm to .5 cm, such as for example .01 cm. The pre-set safety rate of expansion may be set so that each increment of set size takes place once every minute, or two minutes, or three minutes, or some time period in the range of 30.0 seconds to 5.0 minutes, with the rate selected to provide for safe expansionof the tissue wall of the patient, typically allowing the tissue to stretch safely during this period and relax during this period in preparation for a subsequent incremental expansion.

[0061] Optionally, and as needed, the physician may repeat the expansion therapy, or some part of the process, if the treatment completes at a time that significantly precedes the start of stage two labor. For example, the clinician may provide a full therapeutic expansive treatment and find that the dilator achieved a dilation that should achieve a therapeutic effect about three hours earlier than the start of stage two labor, and as such the dilator was removed and therapy completed three or more hours before descent of the neonate. In such a case, the preacclimation process may be repeated. This can address a loss of tissue expansion that resulted due to the tissue returning to its prestretched condition during the time period between completion of the first treatment and the patient beginning stage two of labor. Further, prior to treatment, the physician or clinician may examine the patient and determine if the patient is at risk of surgical intervention, typically an emergency Cesarean section, and based on the assessed risk, the physician may apply the methods described herein to reduce the likelihood of needing surgical intervention due to second stage arrest. As is generally known, and not to be seen as limiting, second-stage arrest during childbirth typically involves labor stalling in the second stage, typically seen as commencing when the cervix is fully dilated and ends with the delivery of the baby. This stage typically involves active pushing, but arrest is diagnosed when there is no progress in fetal descent despite adequate contractions and maternal effort. Common causes include fetal malposition (such as occiput posterior), cephalopelvic disproportion (when the baby's head is too large for the mother's pelvis), inadequate uterine contractions, or maternal exhaustion.

[0062] Figs. 1A-1C depict one example of an electromechanical intrapartum pelvic floor dilator (IPD) that was used with the methods described herein. Fig, 1 A presents a side view perspective of the example IPD and Fig. IB gives an overhead perspective. Fig. 1 C provides a view showing greater detail of a user interface integrated into the handle of the IPD.

[0063] In the example of Figs. 1A-1C, the intrapartum pelvic floor dilator 100 includes rigid or semi-rigid pads mounted on radially expandable arms 102. At the distal end of the intrapartum pelvic floor dilator 100 is a distal release. The distal release is a device that can detect contact with the fetus and upon contact the distal release can cause the dilator 100 to signal the clinician that descent of the neonate has possibly started. In this embodiment, the distal release is a pressure-sensitive mechanism on the distal tip of the device is activated if there is tissue contact with the device, notifying the clinician that treatment may need to be discontinued if the descending fetal head is touching the device In optional embodiments, thedistal release may detect contact with an object and cause the dilator to obtain a contracted configuration for easy removal of the dilator 100 from the patient and to prevent obstructing the path of the fetus through the birth canal.

[0064] Figs. 1 A and IB further depict that the IPD includes a set of arms 102, in this case four arms, i, and Figs. 1 A and 1 B show these arms 102 in a contracted configuration and formed into a cylinder for insertion into the lower birth canal of the patient. The depicted IPD 100 is a diameter expandable IPD that is sized for intravaginal insertion into a nulliparous patient. In the depicted example, the electromechanical IPD device 100 is during pre-deployment and thus before radial expansion, in a contracted state with its arms 102 pulled radially inward to form a cylindrical body about the longitudinal interior axis 106. The example IPD 100 is 12.6 cm long and 3.4 cm in diameter. The IPD 100 is typically inserted 4.0 to 5.0 cm into the vagina when the patient is in active labor, with typically at least 1 hour expected before the second stage of labor, typically at full cervical dilation. The four arms 102 of the IPD 100 expand outward in regulated preselected increments of expansion to gradually expand from about 3.4 cm to 8.0 cm over 60 minutes of treatment time.

[0065] In this depicted IPD 100, there is a processor (not shown), such as a microprocessor or a microcontroller, that is built into the handle 114 of the IPD 100, such that the processor is integral to the IPD 100. The processor is programmable and is configured for expanding the diameter of the IPD 100 in a slow and continuous manner, such that the tissue of the vaginal canal and the surrounding tissue of the pelvis is slowly and gently stretched by the expanding IPD 100. As will be discussed with reference to Fig. 3, this IPD 100 has a processor that, as an initial operation, will drive the arms 102 radially outward with, in this example an essentially equal radial displacement of each of the four arms. In this IPD 100, the initial outward radial expansion increases an amount sufficient such that an initial diameter expansion fits the IPD 100 into engagement with the vaginal wall of the patient and secures the IPD 100 against dislodgement due to the type of movement that occurs during labor. After initial expansion, the processor is configured for therapeutic expansion that dilates the IPD 100 in incremental steps selected to allow substantially even incremental expansion of the diameter over a time period selected to allow a controlled and radially directed force to therapeutically expand patient tissue involved in stage two of labor.

[0066] The IPD 100 shown in FIGS. 1A-1C is formed as a cylinder 124 when in a collapsed configuration as shown in FIGS 1 A and 1 B and can outwardly extend the arms 102 to achieve an expanded configuration as shown in FIG ID. When in the collapsedconfiguration, the IPD 100 has a cylindrical exterior outer wall 124 formed by the rigid or semi rigid pads on each of the respective four arms 102. The long surface of each arm 102 extends parallel to the interior axis 112 of the cylinder 124. As shown in FIG. ID, each arm 102 is an arc-shaped section capable of expanding outward and radially from the interior axis to apply a radially directed force to the tissue of the patient. The arc shaped section is formed from a rigid or semi-rigid curved plastic plate. The curved plastic plate has a series of circumferentially arranged slots that can increase flexibility or help determine the rigidity of the plastic plate. The plastic p can be a biocompatible material of the type commonly used with medical devices that are placed into a biological lumen. Any suitable material can be used as long as it is biocompatible can be formed into the arc-shaped plates of the arms 102 of the type depicted in FIGS 1 A, IB and ID, and it will be understood that several plastic materials can be used including ones commonly used in medical devices due to their biocompatibility, durability, and resistance to chemicals. Polycarbonate (PC) is often chosen for its strength and transparency, making it a common choice for surgical instruments. Polyethylene (PE), particularly high-density polyethylene (HDPE), is used in implants due to its excellent biocompatibility and flexibility. Polypropylene (PP) is widely used because of its chemical resistance and low cost. Polytetrafluoroethylene (PTFE), known as Teflon, is valued for its non-reactivity and smooth surface, making it useful as a material or a covering material. Silicone is another material useful for forming these plates. The arc-shaped plates of the arms 102 may be formed as composites too, to have a plastic body with a coating or layer adhered to the surface of the arc-shaped plate.

[0067] The arc-shaped plates on the arms 102 are rigid or semi-rigid, and as rigid or semi-rigid bodies these plates generally keep their shape and lines of their shape even when engaged with the tissue wall of the patient, but typically offer enough flex, deformation and elasticity to avoid harm to the patient when pressed against the patient tissue, or to avoid forming a point or other shape of sharp contact that would harm the patient. As depicted in FIGS 1A and IB, the arc-shaped plates of arms 102 can include apertures 126 that are placed around the circumference of the arc shaped plate. Such apertures can provide some flexibility to the portion 128 of the arc-shaped plate of arm 102 that will be pressed against the tissue of the patient. There are two rings of equally sized apertures 126 in this example embodiment, but the number of rings, and the size of the aperture as well as shape and location can vary depending upon the mechanical response, such as flex, desired when contacting the tissue of the patient. The rigid arc-shaped plates act to keep the radially directed force directed radially even when pressed against patient tissue and avoid significantdeformation that can direct the force more laterally and thus away from the tissue being expanded.

[0068] Additionally, the depicted example IPD 100 has an electric motor that is integrated into the IPD 100 and operates under the control of the processor. Typically, there is a mechanical assembly to controllably move the arc-shaped plates of arms 102 radially outward from the interior longitudinal axis 112. FIG. IE depicts one example of a handle 114 of an IPD 100 of the type described herein and having an integrated motor 120 and a processor 118. In particular, Fig. IE presents a functional block diagram of a handle 114 of an IPD 100 that has an integrated motor 120 operating under the control of an integrated processor 118. The motor 120 is an electric motor and connects to a mechanical assembly 130 that operates to translate rotational drive of the motor 120 into a mechanical drive that will expand the arms 102 of the IPD 100 from a collapsed configuration to an expanded configuration and in turn from an expanded configuration back to a collapsed configuration, as well as to different states in between the collapsed configuration and the fully expanded configuration. Fig. IE further depicts that the processor 118 can couple via electrical connections 134, typically wires and buses, to a user interface 116, a force sensor 110 and to a battery 132 which may be a removable battery capable of being inserted into a slot within handle 114.

[0069] The processor 118 in one embodiment is a microcontroller of the type commonly used for programmatically operating electrical components and in this case the processor 118 is a microcontroller that has on board programmable memory for storing program instructions for carrying out the methods described herein. Such methods provide for the incremental expansion of the IPD 100 from a collapsed configuration to an expanded configuration. Figs. 2A and 2B illustrate the IPD disposed in a patient in the collapsed configuration and the expanded configuration, respectively, to illustrate the difference between the two configurations.

[0070] During expansion, the processor 118 operates the user interface 116 to receive commands from the user interface such as to expand, contract, stop, commence or other instruction. Additionally, the user interface 116 as depicted in FIG. 1C can include LED's 138 that display information to a clinician. Such information can include the current diameter of the IPD 100 as it goes from the collapsed configuration to the expanded configuration. Additionally, the user interface 116 as depicted in FIG. 1C can include LED's 138 that display time of the process, thus indicating for how long treatment has been underway, or some other time metric. Further additionally, the user interface 116 can present an indicatorsignal that indicates to the clinician that the distal release 104 has been contacted indicating that the distal end of the IPD 100 has been physically touched with enough force to indicate contact of the IPD against an object, and which may be the neonate descending. In any case the user interface 116 can flash a visual indicator to the clinician allowing the clinician to use the user interface 116 to stop expansion, direct retraction of the radial arms and optionally remove the IPD from the patient. In alternate embodiment the indicator can be audible or tactile of some other human detectable signal.

[0071] In the embodiment depicted in FIG. IE the motor 120 is coupled directly to the mechanical assembly 130. The motor 120 rotates under control of the processor 118 and causes the mechanical assembly 130 to translate the rotational motion of the motor 120 into a motion capable of radially expanding the arms 102. In FIG. ID, an example of such a mechanical assembly is shown. In FIG. ID, the mechanical assembly 130 is a mechanical scissor assembly capable of responding to the rotational force of the electric motor 120 by expanding or contracting scissor arms 140 that are centrally pinned about pivot 142 and slidably movable along rails 144 and thereby capable of responding to the rotational motion of the electric motor 120 to moving the scissor arms 140 closer or further apart thereby driving the IPD arms 102 radially outward or inward from the interior longitudinal axis 112.

[0072] The force sensor 110 connects to the processor 118 and the processor 118 can monitor the force sensor 110 output. The force sensor 110 output can be a measure of the force currently being applied by the arms 102 to the tissue of the patient. The processor 118 can store in memory a safety threshold representative of a force value that indicates the upper level of force the IPD 100 is to apply through the arms 102 to the tissue of the patient. The processor 118 can continuously monitor the force sensor 110 to ensure that during each increment of the diameter of the IPD 100, the force being applied by the increasing diameter to the tissue of the patient is below the safety threshold stored in memory of the processor 118.

[0073] This example IPD 100 has a user interface 116 integrated into handle 114 and that allows the clinician to operate User Interface (UI) buttons 136 activate the processor 118 to programmatically expand the diameter of the IPD 100 and move the IPD 100 from its collapsed configuration to its expanded configuration. Optionally, the handle integrated user interface 116 has a display 138 that can indicate the current diameter of the intrapartum pelvic floor dilator. Typically, the display is a visual display in the depicted example can be a set of LEDs located under a translucent biocompatible material and configured to form anumber indicating the present diameter of the IPD 100. Another display 138 provides a warning light that the distal sensor 114 has been contacted.

[0074] As discussed earlier, Fig. ID presents an image of the IPD 100, but in this depiction the arms 102 are radially extended and have increased the diameter of the dilator. In this depicted embodiment, the IPD 100 includes an electric motor that will cause the arms 102 to radially extend outwardly. In one embodiment, the electric motor is under control of the processor 118 and incrementally expands the radial diameter of the device 100 by incrementally extending the arms 102 radially outward. Optionally, the increments can be preselected increments, such as ,05cm, ,1cm. ,2cm or any increment in a range of ,01cm to 2cm. Each increment can be the same, or they may vary over the time period of the therapy. Optionally, the size of the preselected increment can be selected based on the expected treatment time. For example, as shown in Fig. 3 A, the device may begin with an expansion to secure the IPD device 100 in place within the lower birth canal of the human patient. Fig.3 A shows data from an expansion process with time marked in minutes along the X-axis and diameter of the IPD device marked in centimeters along the Y-axis. The expansion may be sufficiently large to secure the arms 102 against the tissue wall of the patient and engage with sufficient force to secure the IPD device 100 within the lower birth canal. The force may be sufficient to keep the IPD device 100 secured within the patient such that the IPD device 100 avoids falling from the patient as the patient goes through the conventional motions of a women in labor. This can include sitting up in bed, rolling over, leaving the bed and other typical cardinals of movement.

[0075] Fig. 3 A shows that after the initial expansion, the device 100 is from about 3.4 cm in diameter of the IPD 100 collapsed configuration, as shown for example in Fig. 2A, to about 6 cm in diameter. This is a partially expanded configuration and secured the IPD device within the patient. In the therapy, the final desired diameter is about 8.0 cm for this therapeutic treatment example. As this example treatment time is set for about 30 minutes, with the initial expansion happening at about 5 minutes, the device is to expand about 2.0 cm over 25 minutes. In one embodiment, the IPD device 100 is set to expand a preselected amount, such as about .167 cm every 2.0 minutes, such that over 25 minutes, the device will expand from 6.0 cm in diameter to about 8.0 cm in diameter. As can be seen from Fig. 3 A, this yields a substantially linear rate of expansion.

[0076] Fig. 3B shows a therapy used in the clinical studies disclosed herein and that takes about 60 minutes to perform the therapeutic pre-acclimation of the patient. Fig. 3B shows data from an expansion process with time marked in minutes along the X-axis anddiameter of the IPD device marked in millimeters along the Y-axis and a measure of force applied to the tissue wall of the patient also marked along the Y-axis. The electromechanical IPD 100 is operated under processor control with the therapy initiated by the clinician controlling the IPD device 100 through use of the interface 116 to begin the therapy. The IPD 100 makes an initial expansion to secure the IPD device 100 within the patient and to also avoid unneeded delay in therapeutic expansion that can arise when the device expands too slowly from its small collapsed state to have a therapeutic effect on the tissue. The device then uses a constant rate of expansion and gradually expands the vaginal introitus and pelvic tissues from a resting diameter of 3.4 cm (the initial diameter of the IPD 100 in its collapsed state) to about 8.0 cm over about a 60 minute treatment period. The final preset diameter of 8.0 cm is 1.0-2.0 cm smaller than the average fetal biparietal diameter. Device placement occurred during active first stage of labor with an estimated more than 1.0 hour until expected complete cervical dilation. As this example illustrates, treatment time is set for about 60 minutes. The initial expansion happens early in the process, typically when the cervix is dilated to about 6.0 cm, and expands to about 5.0 cm, or a diameter sufficient to engage with the tissue wall of the patient. In one embodiment, the IPD device 100 is set to expand at a constate rate and can expand a preselected amount at regular intervals. For example, it may expand by .10 cm every two minutes, so making 30 expansions, with one every two minutes, for the 60-minute treatment period to expand 3.0 cm and going from 5.0 cm to about 8.0 cm in diameter. As can be seen from Fig. 3B, this yields a substantially linear rate of expansion.

[0077] Returning to Fig. 1C, it can be seen that at the proximal end of the IPD device 100 is a handle 114. The handle 114 has an integrated user interface that allows for controlling the expansion of the arms and plates. In the depicted embodiment there are UI controls such as the stop-retract button, a diameter setting and a go-increase button. There is also a dilation time setting which can indicate the amount of time that dilation has been going on for. Further depicted in Fig. ID is that the depicted dilator 100 has a removable battery 132.

[0078] Although Figs. 1 A-1E depict a particular type of pelvic floor dilator 100, it will be understood by clinicians, physicians and others of skill in the art that different types of dilators may be employed with the methods described here in to achieve a therapeutic effect for the patient.

[0079] For the procedures described herein, the IPD device 100 can be sized, shaped, and configured to penetrate approximately the first third, or 3-4 cm, of the vagina, and togradually expand the vaginal introitus from a resting diameter of approximately 2 cm to a fully dilated diameter of approximately 10 cm.

[0080] Fig. 4 illustrates a patient model and shows the dilator intravaginally positioned within the patient. In particular, Fig. 4 depicts a patient model 404 having an instore IPD 400 held in place by an optional retention strap 402 that has an optional cradle 406 for connecting the IPD 400 to the retention strap 402. In this particular embodiment the dilator, such as the IPD device 100 depicted in Fig. 1 A, is held in place by a retention strap that helps to keep the IPD device 100 located in the vagina and crossing the pelvic floor of the patient while the therapeutic expansion takes place. Fig. 5 depicts an MRI model of the vaginal canal of the patient and the location at which the IPD device 100 may be positioned for radially expansion. As depicted in Fig. 5, the IPD device 100 is positioned within the vaginal canal so as to be proximate the pubic bone and applying an expansive force proximate the pubic bone by application of the rigid or semi-rigid arms of the IPD against the tissue wall of the patient. As shown in Fig. 5, the IPD device 100 crosses at least part of the pelvic floor and importantly the pathway that the fetus will travel and is held in this example proximate the patient’s urethra, across the perineal body and levator ani muscles and maintained distal from the cervix.

[0081] The methods described herein maintain the IPD in place for the duration of the therapeutic procedure. Typically, that therapeutic effect is the controlled and gradual stretching of the vaginal canal an amount sufficient to facilitate subsequent delivery of the baby with reduced injury to the patient. To this end, the dilation device can incrementally increase in diameter, consequently increasing the size of the vaginal canal. The incremental increase may be gradual enough to allow for tissue to expand without tearing or otherwise being damaged. Tissue can be expanded gradually such that the tissue material retains sufficient elasticity during the expansion to avoid tearing and damage. As discussed more below with reference to the clinical study results, tissue of the pelvic floor and the vaginal canal can, during many birthing procedures, be subjected to sudden outward force as contractions push the head and shoulders of the baby rapidly through the birth canal and across the pelvic floor. As the baby descends through the birth canal, the fetal head is pushed by contractions past the cervix and through the vaginal canal, which forms a passage through the pelvic floor and the complex of muscles and ligaments that make up the pelvic floor. The fetal head may be large and the area of the average fetal head, in the plane of minimal diameters, measures 70.0 -100.0 cm2and generally has a head circumference of 300.0-350.0 mm, requiring marked distension and deformation of the levator complex, the complex ofmuscles around the ani levator. Given this degree of acute distension, it is remarkable that severe muscular trauma is not more prevalent. By use of the devices and methods herein the vaginal wall and pelvic floor expand a priori the passing of the baby, the tissue wall of the vaginal canal and the tissue of the pelvic floor and are pre-acclimated to allow the passage of the baby with reduced likelihood of complete LAM avulsion, and with reduced likelihood of second stage arrest cesarean intervention, and with reduced likelihood of brachial plexus injury to the infant.

[0082] Figs. 6A and 6B are magnetic image resonance (MRI) images of actual patients not treated with the systems and methods described herein. Fig. 6A illustrates the healthy and uninjured levator complex of a patient, while Fig. 6B illustrates an injured patient. Comparison of the images in Figs. 6A and 6B illustrate that substantial injury of the levator complex can arise during labor. In Fig. 6B it is shown that tissue is torn from the bone structure of the pelvis and the patient has suffered a pelvic muscle injury during labor and passage of the fetus through the vaginal canal. The illustrated example injury is substantial and may resist complete healing. Such injuries to the complex that provide the pelvic floor may arise during labor and delivery and can lead to additional conditions, including prolapse of the bladder and lack of support for the sphincters of the patient, causing incontinence, either permanent or intermittent.

[0083] Figs. 7A and 7B illustrate an alternate view of the therapeutic expansion of an IPD device. In Figs. 7A and 7B there is depicted one example of a vaginal dilation device of the type used with the retention devices described herein. In Fig. 7A, the dilation device is shown inserted into the vagina in a closed configuration. The outer diameter of the dilation device in the closed configuration can be less than 4.0 cm, and this may be used during initial insertion to provide placement with sufficient patient comfort. Fig. 7B illustrates dilation device in an expanded configuration

[0084] Clinical Example Study

[0085] A first in women (FIW) study was undertaken with the objective to evaluate the effectiveness of an intrapartum electromechanical pelvic floor dilator designed to reduce the risk of levator ani muscle (LAM) avulsion during vaginal delivery.

[0086] Methods: A multicenter, randomized controlled trial enrolled nulliparous participants planning vaginal delivery. During the first stage of labor, participants were randomized to receive the intravaginal device or standard-of-care labor management. Fig. 9 sets out the enrollment and study progression for this evaluation study.

[0087] The primary effectiveness endpoint was the presence of full LAM avulsion on transperineal pelvic-floor ultrasound at 3 months. Three urogynecologists performed blinded interpretation of ultrasound images. The primary safety endpoint was adverse events (AEs) through 3 months.

[0088] Results: A total of 214 women were randomized to Device (n = 113) or Control (n = 101) arms. Of 113 Device assignees, 82 had a device placed, of whom 68 delivered vaginally. Of 101 Control participants, 85 delivered vaginally. At 3 months, 110 participants, 46 Device subjects who received full device treatment, and 64 Controls underwent ultrasound for the perprotocol analysis. No full LAM avulsions (0.0%) occurred in the Device group versus 7 out of 64 (10.9%) in the Control group (p = 0.040; two-tailed Fisher’s test). A single maternal serious AE (laceration) was device related; no neonate serious AEs were device related. Conclusions The pelvic floor dilator device significantly reduced the incidence of complete LAM avulsion in nulliparous individuals undergoing first vaginal childbirth.

[0089] Thus, data from this study shows that use of the intrapartum electromechanical pelvic floor dilator in laboring nulliparous individuals reduces the rate of LAM avulsion, an injury associated with serious sequelae including pelvic organ prolapse. In particular, it reduces the rate of complete avulsion.

[0090] Moreover, data from this study shows that use of the intrapartum electromechanical pelvic floor dilator in laboring nulliparous individuals reduces the rate of second stage arrest cesarean section. In fact, this clinical study showed that arrest of labor in the second stage after full dilation yielded intervention in the device group 3.7% (3 / 82 relevant participants) of the time versus intervention in the control group of 6.9% (7 / 101 of the relevant participants). This is a significant and surprising finding. The second stage of labor is the time from complete dilation to delivery of the neonate / infant. Modifiers that affect the second stage length include factors such as parity, epidural anesthesia, delayed pushing, fetal station at complete dilation, maternal body mass index, fetal weight and occiput posterior (OP) position. Such factors were at least considered in this study, and the difference was the therapeutic use of the IPD as disclosed herein. The therapeutic use of the IPD as described herein improved the second stage of labor in nulliparous women helping to provide safe maternal and fetal outcomes. It is noted that in the United States, cesarean section rates are on the rise. Moreover, the most common indication for cesarean section is labor arrest. The IPD systems and methods described herein can help reduce the occurrence of cesarean section procedures.

[0091] Even further, data from this study establishes that the use of the intrapartum electromechanical pelvic floor dilator in laboring nulliparous individuals can be used to reduce brachial plexus injury to the infant. The brachial plexus is a complex network of nerves between the neck and shoulders. These nerves control muscle function in the chest, shoulder, arms, and hands, as well as sensibility (feeling) in the upper limbs. Brachial plexus birth injury may, inter alia, cause arm weakness and loss of motion. It is often caused when an infant's neck is stretched to the side during a difficult delivery..

[0092] Vaginal delivery carries risk of injury to the pelvic floor anatomical structures and this risk is highest in nulliparous individuals. Damage to pelvic floor structural integrity increases the likelihood of developing serious sequelae including pelvic organ prolapse (POP). Specifically, injury to the levator ani muscle (LAM) complex during vaginal delivery occurs in 13-36% of individuals after vaginal birth and is strongly associated with subsequent POP. Over half of women with LAM subsequently develop POP beyond the hymen within the first 6-17 years from first vaginal delivery. Crowning of the fetal head during delivery considerably stretches the LAM and can lead to detachment, or avulsion, of the puborectalis component from its origin at the inferior pubic ramus. Partial or complete LAM avulsion can be quantifiably diagnosed using tomographic ultrasound imaging. Currently, there are no decisive preventive approaches documented in the literature for reducing these injuries to the pelvic floor muscles during vaginal birth. The current study investigated an intrapartum electromechanical pelvic floor dilator (IPD) that was designed to address the biomechanical resistance of pelvic tissues during vaginal birth. Computer models and in vivo MRI estimate that the diameter of the fetal head is 2.5-3.5 times the diameter of the urogenital hiatus through the LAM. This size disparity imposes a remarkable degree of circumferential stretch on the LAM during crowning of the fetal head during the second stage of labor. The combination of rapid and excessive stretching risks LAM injury by exceeding the muscle’s elastic limit. To counter this effect, the IPD slowly stretches the vagina and surrounding pelvic tissues during late first-stage labor, thereby pre-acclimating the LAM and other pelvic floor components to the strain of crowning. A prior study confirmed the feasibility of incorporating an intrapartum vaginal dilator into labor and delivery care. See Orejuela et al. Prospective evaluation of the safety and feasibility of a pelvic floor dilator during active labor. Int Urogynecol J. (2018). . This study tested the hypothesis that the IPD device is a safe and effective intervention to reduce LAM avulsion incidence during first vaginal delivery.

[0093] Materials and Methods

[0094] Study Design and Participants

[0095] This randomized, controlled pilot study evaluated the safety and effectiveness of, and patient satisfaction with, an IPD designed to reduce the incidence of LAM avulsion during

[0096] vaginal birth. The study was performed at 15 tertiary medical centers in the USA.

[0097] Enrollment spanned September 2021 to September 2022. Fig. 9 provides a flowchart of the enrollment and study progression. As can be see from Fig. 9, participants were randomized 1 : 1 during the first stage of labor to either receive the IPD (Device arm) or standard of care (Control arm), in accordance with a computer-generated randomization sequence (www. randomize, net). Study sites were chosen whose enrollment would mirror the diverse background of the contemporary USA populace.

[0098] Inclusion / Exclusion Criteria

[0099] Primary inclusion criteria were nulliparous individuals aged > 18.0 years planning first singleton vaginal delivery at term (> 36 weeks), with willingness to receive epidural anesthesia prior to randomization. Primary exclusion criteria were fetal chromosomal or structural anomalies, local or systemic infection, maternal history of connective tissue disorders or neurological disease that could impact delivery, or unresolved intrapartum category 2-3 fetal heart tracing prior to randomization.[000100] IPD Device and Procedure[000101] The electromechanical IPD is a single-use intravaginal device (see Figs. 1 A, IB and ID). Pre-deployment, the IPD device is 12.6 cm long and 3.4 cm in diameter. The device is inserted 4.0-5.0 cm into the vagina when the patient is in active labor, with at least 1 hour expected before the second stage of labor. The four arms of the IPD expand outward in regulated increments to achieve gradual expansion from 3.4 cm to 8.0 cm over 60 minutes. The device gradually expands the vaginal introitus and pelvic tissues from a resting diameter of 3.4 cm to 8.0 cm over ~60 minutes. The final preset diameter of 8.0 cm is 1.0-2.0 cm smaller than the average fetal biparietal diameter. Device placement occurred during active first stage of labor, with more than 1 hour estimated remaining until complete cervical dilation. Device expansion was controlled by a mechanism that is designed to expand slowly at a constant rate, thereby gently prestretching the vagina and surrounding pelvic muscles. The device could be stopped and quickly retracted by the operator at any time and for any reason (e.g., to perform cervical examinations). Device diameter was displayed on the handle user interface. The device includes a force sensor and was force limited and would not continue expansion if the vaginal wall / pelvic floor pressures exceeded a predefined safetythreshold. A pressure-sensitive mechanism on the distal tip of the device is activated if there is tissue contact with the device, notifying the clinician that treatment may need to be discontinued if the descending fetal head is touching the device. After IPD therapy was complete and the device reached maximal dilation, the device arms were retracted and the device removed. If the second stage of labor had not ensued within 3 hours of removal, treatment could be repeated at the discretion of the clinician.[000102] All investigators were trained in IPD use and study protocols. Per protocol, all participants received epidural anesthesia prior to randomization. Reasons for not employing the IPD in participants randomized to the Device arm included, for example, rapid cervical dilation and changes in fetal heart tracing. After device removal, inspection of the vagina and perineum was performed to identify any lacerations or bleeding. Participants in both groups who underwent Cesarean section (C-section) after randomization were withdrawn from the study.[000103] Follow-up Schedule[000104] Participants were asked to return three months after vaginal delivery for ultrasound examination, inquiry into symptoms and quality of life using the Pelvic Floor Impact Questionnaire-7 (range 0-300 points; 300 = maximum negative impact) and the Pelvic Floor Distress Inventory -20 (range 0-300 points; 300 = maximum distress) tools See Barber MD, et al; Short forms of two condition- specific quality-of-life questionnaires for women with pelvic floor disorders (PFDI-20 and PFIQ-7). Am J Obstet Gynecol. (2005), and were queried on general device-related satisfaction on a 1-10 analog scale (10 = highest). Ultrasound examination was performed in accordance with American Institute of Ultrasound in Medicine / International Urogynecological Association (AIUM / IUGA) practice parameters for urogynecological ultrasound examinations. See AIUM / IUGA. Practice parameter for the performance of urogynecological ultrasound examinations: developed in collaboration with the ACR, the AUGS, the AU A, and the SRU. J Ultrasound Med. (2019). . Three-dimensional transperineal / translabial ultrasound was performed with GE Voluson systems (Model S6 or newer; General Electric, Boston, MA, USA) with the patient in the supine position and an empty bladder during rest, maximum Valsalva, and pelvic floor muscle contraction. The plane of minimal hiatal dimensions at maximal pelvic floor muscle contraction was used for tomographic imaging of the puborectalis component of the LAM, with an interslice interval of 2.5 mm. As previously described in Dietz HP et al.; Tomographic ultrasound imaging of the pelvic floor: which levels matter most? Ultrasound Obstet Gynecol. (2009), a full avulsion, unilateral or bilateral, was defined as an interruption between bone and muscleobserved in at least three central tomographic slices (Fig. 8). Fig. 8 presents tomographic imaging transperineal tomographic ultrasound images of the LAM. Sequent! al -level ultrasound imaging reveals full left-sided avulsion (white arrows in Fig. 8) of the levator ani pelvic floor muscle group three months after vaginal delivery. The avulsion injury appears as a frank interruption in the smooth arcing topography of the intact LAM complex seen on the contralateral (right) side in these ultrasound images. Trauma, whether unilateral or bilateral, was quantified using a tomographic trauma score (TTS) that ranks LAM injury on a 0-12 scale, with “0” = no injury and “12” = complete bilateral avulsion. See Dietz HP, et al; Low GK. All or nothing? A second look at partial levator avulsion. Ultrasound Obstet Gynecol. (Nov. 2022). Three board-certified urogynecologists, each with 15-20 years of experience interpreting images who were blinded to randomization and delivery details, independently reviewed the ultrasound images using GE 4dView software (General Electric). Differences in diagnosis were resolved through review of the images in conference to achieve agreement by at least two readers. If ultrasound images were indeterminate for LAM status the participant was asked to return for a repeat ultrasound.[000105] Outcome Measures[000106] The primary effectiveness endpoint was the rate of pelvic muscle injury, defined as complete LAM avulsion diagnosed by transperineal ultrasound of the pelvic floor anatomy at three months postpartum. Secondary effectiveness measures included rates of partial LAM avulsion, perineal lacerations, obstetric anal sphincter injuries (OASIS) (See Dietz HP. Exoanal imaging of the anal sphincters. J Ultrasound Med. (2018)), conversion to C-section owing to arrest of the second stage of labor, and duration of the second stage of labor.[000107] Statistical Analysis[000108] Categorical variables were compared using the Chi-squared test, with reversion to Fisher’s exact test for evaluating the primary effectiveness outcome when any value on 2 * 2 contingency tables was < 5. Continuous variables were compared using Student’s t test when the data were normally distributed, and the Wilcoxon rank sum test when not normally distributed. Two-tailed p values < 0.05 were considered indicative of significant differences. Statistical software was SAS v.9.4 (SAS Institute, Cary, NC, USA). The original power calculation was based on a primary endpoint of the incidence of both partial and full avulsions. With feedback from the FDA regarding the uncertainty related to the healing of partial avulsions, the primary efficacy endpoint was chosen to be full LAM avulsion rate at 3 months. This change rendered our original power analysis (based on 80% power to detect a > 50% reduction in full and partial LAM injury with device use, at a two-tailed 0.05 type 1error rate) invalid. A per-protocol population was analyzed consisting of those participants who delivered vaginally, completed treatment defined as device expansion to at least 6.7 cm, and returned for 3 -month follow-up ultrasound. During the time delay between randomization and planned device placement, some device-arm participants underwent a C-section for fetal intolerance to labor or experienced rapid progression to complete cervical dilation, precluding device placement; these participants were excluded from analysis. The safety population included individuals who were randomized and received the device.[000109] Results[000110] Of 492 individuals who were screened and consented to participate, 214 participants were enrolled in the study and randomized to the Device (n = 113) and Control (n = 101) arms. The study flow diagram is shown in Fig. 9. Demographics were equivalent between study arms (Fig. 10 showing Table 1 of the study and the demographic comparison). Of 113 participants randomized to the treatment arm, 82 (72.6%) had an IPD placed; 31 were precluded from device placement because of full cervical dilation (n = 25), no available device and / or trained provider (n = 4), subject decision (n = 1), or C-section (n = 1). There were 14 C-section conversions in the Device arm after IPD treatment. Of the 68 treated participants who delivered vaginally and completed device treatment, 46 (67.6%) returned for 3-month postpartum ultrasound. Of the 101 Control participants, 85 experienced a vaginal delivery and 64 of these (75.3%) returned for the 3-month ultrasound. Timing from delivery until ultrasound imaging was a median 106 days (interquartile range 93-140 days) in the Device arm and 103 days (interquartile range 92-129 days) in the Control arm.[000111] Labor and delivery characteristics are shown in Table 2 set out in Fig. 11. Average gestational age in both groups was 39.2 weeks. Labor was induced in 87.8% and 76.2% of participants in the Device and Control groups respectively (p = 0.045). There was no difference between the two groups in rates of episiotomy, perineal tears, or instrument- assisted vaginal delivery. The rate of C-section conversion for active phase arrest of or fetal intolerance to labor, rate of C-section for second-stage arrest, median duration of the second stage of labor for vaginal deliveries, and birthweights were all similar between groups. However, for the Device group the study established a reduction in second stage arrest c- section, with the Device group having 3.7 % (3 / 82) c-section interventions due to second stage arrest versus the higher 6.9% (close to twice the rate) (7 / 101) for the Control ground. Use of the IPD device and therapy of this study reduced the occurrence of second stage arrest c-section in nulliparous women. Median IPD treatment time was 62 min.[000112] Of 82 participants in the Device group, 46 (56.1%) received complete treatment with the device (expansion to > 6.7 cm), delivered vaginally, and returned for 3-month postpartum pelvic floor ultrasounds. Among thelOl participants in the Control group 64 (63.4%) delivered vaginally and returned for the postpartum ultrasound (Fig. 2). The rate of complete avulsions was significantly reduced in the Device group (0.0%, 0 / 46) versus Controls (10.9%, 7 / 64; p = 0.040; See Fig. 12 which sets out Table 3 of the study). Use of the IPD device and therapy of this study reduced the occurrence of full avulsion in nulliparous women. No differences existed between groups in the rate of partial avulsions or combined (partial + complete) avulsions. Anal sphincter injuries occurred at similar rates and severities in both groups.[000113] Rates of total maternal labor and delivery- and / or device-related, nonserious AEs were similar in the two arms (See Fig. 13 which sets out Table 4 of the study). There were 5 cases (6.1%) of vaginal abrasion or bruising recorded in the Device arm versus none in the Control arm (p = 0.012). Chorioamnionitis was diagnosed in 9 (11.0%) participants in the Device arm and 6 (5.9%) participants in the Control arm (p = 0.33). Sixteen participants (19.5%) in the Device arm and 9 participants (8.9%) in the Control arm reported at least one serious AE (SAE; p = 0.038); however, nearly all SAEs in the Device arm were judged to be unrelated to using the IPD device during vaginal delivery (See Fig. 13 which sets out Table 4 of the study). This included three participants who developed preeclampsia with severe features and three individuals with non-obstetrical related infections (cholecystitis, appendicitis, mastitis). The proportion of Device participants (12 out of 82) and Control participants (7 out of 101) with SAEs that were related to either the device and / or labor and delivery were similar (p = 0.09). The single device-related SAE was a vaginal laceration seen after device removal, associated with significant bleeding, and the need for extensive suturing. Postpartum hemorrhage was noted in 5 Device participants^.1%) and 7 Control participants (6.9%) (p = 0.82). The rate of neonatal SAEs was similar in the two arms (See Fig. 13 which sets out Table 4 of the study). There was one reported occurrence of respiratory distress and 1 of fetal distress in the Device arm. There were two cases of respiratory distress and hypoxic ischemic encephalopathy in the Control arm, conditions which seem unrelated to the labor and delivery process. However, as Table 4 of Fig. 13 reports, there were no (0 / 82) cases of Brachial plexus injury in the Device group as compared to two (2.0 / 101) cases of Brachial plexus injury in the Control group. This study established that use of the IPD device and therapy of this study reduced the occurrence of brachial plexus injury in the infant during birth. There was no difference between groups with regard to the proportion of neonates bornwith an Apgar score < 7 at 5 min. All 110 participants who returned for 3 -month follow-up ultrasounds also completed the Pelvic Floor Impact Questionnaire-7 (PFIQ-7), Pelvic Floor Distress Inventory-20(PFDI-20), and satisfaction survey (See Fig. 14 which sets out Table 5 of the study). The mean PFIQ-7 impact score was 40% lower (better) in Device participants (12.4 points) than in Controls (20.6 points); however, this difference did not reach statistical significance (p = 0.24). Similarly, although the mean PFDI-20 distress score was 17% lower (better) in the Device group (30.9 points) versus Controls (37.2 points), these differences were similar (p = 0.35). Participants in the device arm provided an assessment of their experience and whether they would recommend the device to others on a scale of 0-10, where higher scores indicate more favorable response. The mean response was 7.7, demonstrating that participants were generally satisfied with the use of the device during their labor.[000114] Discussion[000115] In this pilot study, use of the electromechanical IPD device significantly reduced the risk of full LAM avulsion — no participant in the Device-treatment group experienced full LAM avulsion. This result supports the concept that the elasticity of the pelvic floor muscles can be gradually enhanced through mechanical stretching prior to delivery of the fetal vertex, resulting in reduced likelihood of LAM avulsion from its attachment at the pubic rami. This is consistent with the findings of a previous feasibility study using an earlier version of the device.[000116] The mechanism for reducing pelvic floor injury with use of the IPD device is based on the properties of the pelvic floor muscles. Research in sports medicine indicates that muscle and connective tissues are viscoelastic and elasticity is strain-rate dependent, i.e., the slower a muscle is stretched, the less likely it is that there will be injury. See Chen CH, et al.; Acute effects of static active or dynamic active stretching on eccentric-exercise-induced hamstring muscle damage. Int J Sports Physiol Perform. (2015).. In the second stage of labor, the pelvic floor muscles experience rapid distension. MRI-based computer modeling shows that the distal-most pelvic muscles comprising the levator complex must lengthen by a factor of 3-4 during fetal head crowning. See Sindhwani N, et al.; In vivo evidence of significant levator ani muscle stretch on MR images of a live childbirth. Am J Obstet Gynecol. (2017); and Hoyte L, et al.; Quantity and distribution of levator ani stretch during simulated vaginal childbirth. Am J Obstet Gynecol. (2008). Classic teaching in obstetrical care emphasizes the role of the clinician in limiting the rate of pelvic floor stretch during delivery by supportingthe perineum and controlling the speed of head expulsion. See Committee on Practice Bulletins-Obstetrics. ACOG practice bulletin no. 198: prevention and management of obstetric lacerations at vaginal delivery. Obstet Gynecol. (2018). Paradoxically, the extreme dilation of the pelvic tissues during childbirth creates resistance that impedes and slows delivery of the baby, and simultaneously over-stretches and injures pelvic tissues. The currently investigated electromechanical IPD device and method of treatment slowly prepares the pelvic floor muscles by maximizing their stretch prior to delivering the fetal head.[000117] A major benefit of reducing levator ani injury risk during vaginal delivery is the probable reduced risk of developing POP later in life, an association that appears to strengthen over decades. Indeed, 55% of women with LAM avulsion develop POP within 6- 17 years after first delivery compared with 21% of women without LAM avulsion. Injury to the LAM may also increase the likelihood of developing stress incontinence, although that relationship is equivocal. To exclude potential pre-existing pelvic floor injury in our cohort, we only enrolled nulliparous individuals. Second vaginal deliveries do not seem to have a deleterious effect on LAM biometry and structural integrity .[000118] The IPD device had a favorable safety profile when used as an adjunct during the first vaginal delivery. Nonserious vaginal abrasion / bruising identified in five Device participants (6.1%) was considered a device-related minor AE; there were no cases of vaginal abrasion or bruising reported in the Control arm. The study protocol instructed investigators to examine the vaginal walls for any evidence of tissue injury after device removal. This may have introduced bias because no intrapartum examination of the vagina was required for the Control arm.[000119] A significant difference was recorded between the two groups for SAE occurrence. However, of the 16 participants in the Device group with a maternal SAE, three were preeclampsia with severe features, two were cases of retained placenta, and three were related to non-obstetrical infection. None of these complications was device related. There was no significant difference in the incidence of L&D and device-related SAEs between the Device and Control groups (14.6% vs 6.9% respectively, p = 0.09). The only device-related SAE reported was a vaginal laceration seen after device removal that required extensive suturing to achieve hemostasis. Of note, that participant had a nonreassuring fetal heart tracing that required maternal lateral repositioning multiple times. In addition, her vaginal mucosa was very friable and denuded, which contributed to the challenges in controlling bleeding. Subsequently, the instructions for use of the device were changed to limit the number of maternal repositioning maneuvers with the device in place and to excludeindividuals identified with friable vaginal tissue prior to randomization. The rates of chori oamnionitis and endometritis were statistically similar in the Device and Control arms, suggesting that the presence of an intravaginal device in labor does not enhance the risk of ascending bacterial microbes and infection. The number of cervical examinations performed during labor is an independent risk factor for the development of clinical chori oamnionitis. Placement of the IPD does not require a digital examination of the vagina or cervix. Once the device is placed, there is no requirement for additional internal examinations. Unlike intrauterine pressure catheters that are inserted through the cervical canal and into the uterine cavity providing a potential pathway for ascending bacteria, the IPD in this study was placed only 4.0-5.0 cm within the vaginal canal.[000120] Not to be limited by theory, but it has been thought that pre-stretching of the pelvic floor with the device would mimic the perineal massage technique that has been shown to potentially reduce the risk of serious perineal lacerations. See Aasheim V, et al.; Perineal techniques during the second stage of labour for reducing perineal trauma. Cochrane Database Syst Rev. (2017). The incidence of ultrasound-diagnosed OASIS in the Device and Control arms was similar. Taken together with the significant reduction in complete LAM avulsion rate, the IPD device appears effective for stretching and preparing the pelvic floor muscles to accommodate rapid delivery of the newborn, but does not have a discernable impact on perineal / anal sphincter injury rates. Participants who employed the IPD device reported favorable impressions and experiences, with no negative impact on quality of life.[000121] A primary study limitation was the mid-study protocol change to a more stringent primary efficacy outcome (i.e., full avulsion rate instead of combined partial + full avulsion rate). The reasoning behind this change was that low-grade partial avulsions may potentially heal postoperatively and thus have limited clinical significance, whereas a fully avulsed LAM is unlikely to spontaneously reattach after injury. Another limitation was the necessary partial blinding design, which may have introduced unintentional bias in recording peripartum events, including AE rates. This did not impact the blinded assessment of LAM avulsion on ultrasound images. Several Device participants converted to C-section or experienced rapid progression to full cervical dilation before randomization; thus, LAM injury findings of this study are not generalizable to the subgroup of individuals with a rapid first-stage labor.[000122] Study recruitment was aimed at including populations with a history of receiving inequitable care for pelvic floor disorders. Participants approximated the proportion of Black individuals and exceeded that of Asian people currently present in the diversifying USA populace, and our findings of reduced LAM avulsion with IPD use are likely to apply to adiverse group of labor patients. A study currently ongoing with larger planned enrollment should permit detailed subgroup analyses. In conclusion, the electromechanical IPD device reduced the prevalence of full LAM avulsion, a surrogate endpoint for developing POP. Counseling pregnant individuals on the risk of long-term sequelae of vaginal delivery is not typically provided during antenatal care. Other than avoiding use of obstetrical forceps, there are few tools available for preventing LAM avulsion. Incorporating the IPD into obstetrical practice may prove beneficial for protecting against pelvic floor injuries responsible for future POP.[000123] The embodiments described herein are not to be understood as limiting and various modifications and additions may be applied to these embodiments without departing from the scope hereof. Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The breadth of the invention is not to be limited by the subject specification, but rather only by the plain meaning of the claim terms employed.

Claims

CLAIMSWhat is claimed is:

1. A method for reducing full levator ani muscle (LAM) avulsion during vaginal delivery in a nulliparous patient, comprising: identifying a time during stage one of labor for inserting an intrapartum pelvic floor dilator into the patient and, and inserting the intrapartum pelvic floor dilator within the vagina of the patient, for a period of time of between 30 minutes and 90 minutes, automatically expanding the intrapartum pelvic floor dilator during labor to pre-acclimate the vaginal canal and surrounding pelvic tissue of the patient by expanding the vaginal canal and pelvic tissue from a resting diameter of about 3 cm to a resting diameter of about 1 to 2 cm smaller than the average fetal biparietal diameter, and removing the intrapartum pelvic floor dilator from the vagina of the patient prior to full cervical dilation of the patient.

2. The method of claim 1, wherein identifying the time during stage one of labor for insertion of the intrapartum pelvic floor dilator includes identifying a time when cervical dilation has reached about 6 cm.

3. The method of claim 1, wherein automatically expanding the intrapartum pelvic floor dilator includes providing within the intrapartum pelvic floor dilator an electric motor and a processor configured to operate the electric motor to electromechanically, and under control of the processor, expand a diameter of the intrapartum pelvic floor dilator.

4. The method of claim 3, wherein the intrapartum pelvic floor dilator includes an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the intrapartum pelvic floor dilator.

5. The method of claim 3, wherein processor is configured to expand the intrapartum pelvic floor dilator by incrementally expanding the diameter of the intrapartum pelvic floor dilator by a preselected increment.

6. The method of claim 3, wherein expanding the intrapartum pelvic floor dilator comprises sequentially increasing the diameter of the intrapartum pelvic floor diameter by preselected increments of time to achieve a substantially linear rate of expansion.

7. The method of claim 1, further comprising measuring a force applied by the expanding intrapartum pelvic floor dilator to a vaginal wall or a pelvic floor of the patient and continuously comparing the measured force to a safety threshold.

8. The method of claim 1, including expanding the diameter of the intrapartum pelvic floor dilator at an expansion rate below a pre-set safety threshold rate of expansion.

9. The method of claim 1, including measuring an elapsed time since removing the intrapartum pelvic floor dilator, and reinserting the intrapartum pelvic floor dilator and repeating the method for reducing full levator ani muscle if the measured elapsed time from removing the intrapartum pelvic floor dilator is more than three hours.

10. The method of claim 1 wherein inserting the intrapartum pelvic floor dilator includes having the intrapartum pelvic floor dilator transverse at least part of the pubic bone and at least part of the pelvic floor and having the intrapartum pelvic floor dilator engaged to the lower birth canal proximate the urethra, across the perineal body and levator ani muscles and maintained distal from the cervix.

11. The method of claim 1 further including administering an epidural.

12. The method of claim 1, further including providing the intrapartum pelvic floor dilator with a user interface integrated into the intrapartum pelvic floor dilator and being capable of indicating the current diameter of the intrapartum pelvic floor dilator.

13. A method for reducing an occurrence of second stage arrest cesarean section delivery in a nulliparous patient, comprising: inserting an intrapartum pelvic floor dilator within the vagina of the patient, for a period of time of between 30 minutes and 90 minutes, expanding the intrapartum pelvic floor dilator during labor to pre-acclimate the patient by expanding the intrapartum pelvic dilator from a diameter of about 3 cm to a diameter of about at least 6 cm, andremoving the intrapartum pelvic floor dilator from the vagina of the patient.

14. The method of claim 13 including, prior to inserting the intrapartum pelvic floor dilator, examining the patient and determining if the patient is at risk of needing an emergency cesarean section.

15. The method of claim 13, wherein expanding the intrapartum pelvic floor device includes incrementally expanding the diameter of the intrapartum pelvic floor dilator by a preselected increment.

16. The method of claim 13, wherein expanding the intrapartum pelvic floor dilator includes sequentially increasing the diameter of the intrapartum pelvic floor diameter at preselected increments of time to achieve a substantially linear rate of expansion.

17. The method of claim 13, further comprising measuring a force applied by the expanding intrapartum pelvic floor dilator to a vaginal wall or pelvic floor of the patient and comparing the measured force to a safety threshold.

18. The method of claim 13, including expanding the diameter of the intrapartum pelvic floor dilator at an expansion rate below a pre-set safety threshold rate of expansion.

19. The method of claim 13, wherein expanding the intrapartum pelvic floor dilator includes providing within the intrapartum pelvic floor dilator an electric motor and a processor configured to operate the electric motor to electromechanically, and under control of the processor, expand a diameter of the intrapartum pelvic floor dilator.

20. The method of claim 19, wherein the intrapartum pelvic floor dilator includes an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the intrapartum pelvic floor dilator.

21. A method for reducing an occurrence of brachial plexus injury to a neonate during delivery by a patient, comprising: inserting an intrapartum pelvic floor dilator within the vagina of the patient, for a period of time of between 30 minutes and 90 minutes, expanding the intrapartumpelvic floor dilator during labor to pre-acclimate the patient by expanding the intrapartum pelvic dilator from a diameter of about 3 cm to a diameter of about at least 6 cm, and removing the intrapartum pelvic floor dilator from the vagina of the patient.

22. The method of claim 21, wherein expanding the intrapartum pelvic floor device includes incrementally expanding the diameter of the intrapartum pelvic floor dilator by a preselected increment.

23. The method of claim 21, wherein expanding the intrapartum pelvic floor dilator includes sequentially increasing the diameter of the intrapartum pelvic floor diameter at preselected increments of time to achieve a substantially linear rate of expansion.

24. The method of claim 21, further comprising measuring a force applied by the expanding intrapartum pelvic floor dilator to a vaginal wall or pelvic floor of the patient and comparing the measured force to a safety threshold.

25. The method of claim 21, including expanding the diameter of the intrapartum pelvic floor dilator at an expansion rate below a pre-set safety threshold rate of expansion.

26. The method of claim 21, wherein expanding the intrapartum pelvic floor dilator includes providing within the intrapartum pelvic floor dilator an electric motor and a processor configured to operate the electric motor to electromechanically, and under control of the processor, expand a diameter of the intrapartum pelvic floor dilator.

27. The method of claim 26, wherein the intrapartum pelvic floor dilator includes an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the intrapartum pelvic floor dilator.

28. An apparatus for reducing injury during delivery of a neonate by a laboring nulliparous patient, comprising: a diameter expandable intrapartum pelvic floor dilator sized for intravaginal insertion into a nulliparous patient, a processor integrated within the intrapartum pelvic floor dilator and configured for expanding a diameter of the intrapartum pelvic floor dilator such that:an initial diameter expansion fits the intrapartum pelvic floor dilator into engagement with the vaginal wall of the patient and secures the intrapartum pelvic floor dilator against dislodgement due to the type of movement that occurs during labor, and a therapeutic expansion that dilates the dilator in incremental steps selected to allow substantially even incremental expansion of the diameter over a time period selected to allow a controlled and radially directed force to therapeutically expand patient tissue involved in stage 2 of labor.

29. The apparatus of claim 28, wherein the intrapartum pelvic floor dilator is formed as a cylinder having a collapsed configuration and an expanded configuration, the collapsed configuration having a cylindrical exterior outer wall with a long surface extending parallel to an interior axis of the cylinder and having a plurality of arc-shaped sections capable of expanding outward and radially from the interior axis to apply a radially directed force to the tissue of the patient, and an electric motor integrated into the intrapartum pelvic floor dilator and operating under control of the processor and that couples to a mechanical assembly to controllably move the arc-shaped sections radially outward from the interior axis.

30. The apparatus of claim 28, further including an integrated user interface to allow a treating clinician to activate the processor to programmatically expand the diameter of the intrapartum pelvic floor dilator.

31. The apparatus of claim 28 further including a user interface integrated into the intrapartum pelvic floor dilator and being capable of indicating the current diameter of the intrapartum pelvic floor dilator.

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