Intrauterine Monitoring and Contraceptive Systems

Abstract

An intrauterine monitoring system is described. The system includes an intrauterine device shaped and dimensioned for implantation within the uterus and a receiving device. The intrauterine device is for measuring conditions within the uterus to generate sensor data and for functioning as a contraceptive device to prevent pregnancy. The receiving device is for wirelessly receiving sensor data generated by the implantable sensor device of the intrauterine device.

Description

[Technical Field]

[0001] The present invention relates to an intrauterine monitoring and contraceptive system. Embodiments of the present invention relate to a system for both long-term, real-time in-vivo measurement of biophysical parameters within the human uterus and for contraceptive function. [Background technology]

[0002] An intrauterine device (IUD) is an implantable contraceptive device. Currently, contraceptive IUDs chemically or physically destroy the uterus to prevent a fertilized egg from implanting. They are effective contraceptive devices because they do not depend on the patient to perform a task (e.g., taking oral contraceptive pills daily), are long-term (greater than 5 years), and are non-permanent. Contraceptive IUDs are designed to be implanted in the uterus for months to years, during which time the uterine function and intrauterine environment (i.e., biophysical parameters such as temperature, dissolved oxygen concentration, pH, glucose, etc.) of the uterus may change in response to, for example, hormonal changes as the patient ages. Abnormal changes in the intrauterine environment may act as an early indicator for diseases such as endometrial cancer or conditions such as endometriosis. However, current contraceptive IUDs are unable to provide long-term in vivo monitoring to detect these changes within the uterus.

[0003] The present invention aims to address these limitations. Summary of the Invention

[0004] According to one aspect of the present invention, there is provided an intrauterine device shaped and dimensioned for implantation within a uterus; a receiving device, an intrauterine device for measuring conditions within the uterus to generate sensor data and for functioning as a contraceptive device to prevent pregnancy; An intrauterine system is provided, wherein the receiving device is for wirelessly receiving sensor data generated by the intrauterine device.

[0005] In this way, the IUD can monitor and collect data on the intrauterine environment over time. Intrauterine devices (IUDs) can be kept small and simple, requiring only the mechanical and electronic structure necessary to take sensor readings and transmit them to a receiving device, as well as a means to chemically or physically disrupt the intrauterine environment to prevent implantation of a fertilized egg.

[0006] Preferably, the receiving device is operable to wirelessly charge the IUD. In this way, a battery may not be required in the IUD or its size can be minimized, allowing it to be made more compact and avoiding potential problems associated with battery leakage inside the uterus.

[0007] Preferably, the IUD is shaped to anchor within the uterus. This prevents the IUD from migrating within the uterus, ensuring effective contraception, and assists in effective wireless communication with the receiving device.

[0008] Preferably, the IUD is shaped to contact at least a portion of the uterine lining within the uterus.

[0009] Preferably, at least the portion of the IUD that contacts the uterine lining prevents pregnancy by impeding the growth of the uterine lining in a manner that affects implantation of a fertilized egg.

[0010] Preferably, the IUD releases chemicals into the uterus to disrupt the environment inside the uterus.

[0011] Preferably the chemical is provided in or as a coating on a portion of the intrauterine device, or is provided in or as a coating on a portion of the intrauterine device.

[0012] Preferably, the chemical is hormonal, such as a progestin or estrogen, or non-hormonal, such as copper.

[0013] Preferably, wireless charging can be performed using electromagnetic field coupled wireless energy transfer. The receiving device may include an antenna, transceiver circuitry, and a power source, and the IUD may include an antenna, charging circuitry, and a controller. The receiving device may be operable to transfer power from an antenna of the receiving device to an antenna of the IUD via electromagnetic coupling. The power is used by the charging circuit to store power to operate the IUD's sensors and to transmit sensor data to a receiving device.

[0014] Preferably, the IUD includes a capacitor or a rechargeable battery, and the charging circuit can store power by charging the capacitor or the rechargeable battery.

[0015] The power source may be a rechargeable battery.

[0016] Preferably, the receiving device has a controller and a primary coil for wirelessly communicating with the intrauterine device, the receiving device being operable to wirelessly charge the intrauterine device via inductive coupling between the primary coil and the secondary coil; The quality factor of the primary coil is controllable, The controller is operable to control the quality factor of the primary coil to be higher when the receiving device is wirelessly charging the intrauterine device than when the receiving device is receiving sensor data from the intrauterine device, and the receiving device drives the primary coil to operate at a frequency on the order of 100 kHz.

[0017] As a result of the controllable quality factor, the same coil can be used for both efficient power transfer (wireless charging) by using the coil in a (relatively) high quality factor mode, and reliable data communication by using the coil in a (relatively) low quality factor mode.

[0018] The quality factor may be controllable by varying the electrical resistance associated with the primary coil. For example, a damping resistor can be switched in and out of series with the primary coil.

[0019] The quality factor of the primary coil may be selectable between a number of different levels. In a simple case, this could be two levels: a high level for wireless charging and a low level for receiving and / or transmitting data. In more complex cases, this could be, for example, three levels with an intermediate quality factor where different quality factors are optimal for transmitting data compared to receiving data. For example, different data rates may be used for transmission and reception. If a higher data rate is used for reception, the quality factor will be lower since reception requires a higher bandwidth. All other factors being equal, a coil with a relatively high quality factor will output a higher field strength than one with a relatively low quality factor, given the same input power. This makes wireless charging more efficient. A coil with a relatively high quality factor corresponds to a lower resistance in the coil circuit, and as a result generates less heat than a lower quality factor coil for the same input power. This has advantages for heat and thermal distribution within the receiving device.

[0020] Another reason for providing multiple different quality factors is to provide robustness to the communication link when the user is in close proximity to a metallic environment. For example, if a user is sitting in a car or sitting on a metal chair, and the system is operating at a high quality factor, the presence of the metal may detune the system, causing power transfer and / or communication to fail. However, a system with a lower quality factor will waste more power, which is generally undesirable and can be unacceptable for devices that require relatively low power consumption. To alleviate this problem, the system can be configured to adaptively change the quality factor to accommodate the external environment while maintaining reasonable battery life.

[0021] The receiving device may comprise a coil circuit, the coil circuit comprising a primary coil and a damping resistor, the damping resistor switched in series with the primary coil to reduce the quality factor of the primary coil. The coil circuit may include one or more additional damping resistors, different ones of the damping resistors used to control the amount of degradation of the quality factor, or a combination thereof.

[0022] Preferably, the IUD comprises a single-axis antenna and the receiving device comprises a Helmholtz coil, the Helmholtz coil being arranged in communication with the single-axis antenna to wirelessly charge the intrauterine device and receive sensor data.

[0023] The single axis antenna may be configured to operate at a frequency of the order of 100 kHz, preferably in the range 119 kHz to 140 kHz, preferably 130 kHz to 140 kHz, preferably 139.6 kHz.

[0024] The IUD may include one or more of a temperature sensor, a pH sensor, and a dissolved oxygen sensor. These sensors, which may be miniaturized electrochemical sensors integrated into an IUD, are particularly suitable for human fertility analysis applications. Other biophysical parameter sensors may also be used, for example electrical conductivity sensors or pressure sensors may be provided. In some cases, multiple sensors of the same type (eg, temperature sensors) may be provided at different locations on the IUD, for example, in the form of a sensor array. This allows separate measurements to be taken in different regions within the uterus. For example, a first temperature sensor may be located at one end of the IUD adjacent to the cervix, while a second temperature sensor may be located at the other end of the IUD further within the uterus. In this way, the temperature distribution or gradient can be inferred.

[0025] The IUD may comprise a body and one or more arms that project laterally from the body for anchoring the sensor within the uterus. This should increase the likelihood that the device will remain in place throughout the desired implantation period. The IUD may include a pair of arms positioned at or adjacent one end of the body and extending generally away from one another. These structures have been found to provide stable placement of the IUD within the uterus.

[0026] The receiving device may be a wearable receiving device.

[0027] By making the receiving device wearable, it can be kept in relatively close proximity to the IUD over the long term, making regular monitoring easier.

[0028] The receiving device may be provided on the garment. Clothing can be an effective means of ensuring that the receiving device is held adjacent to the user in a generally fixed position for an extended period of time.

[0029] The garment may be, for example, underwear worn adjacent to the uterus or a belt worn around the waist of the user. Alternatively, the wearable receiving device may be a sanitary napkin. As a result, the system causes minimal disruption to the user's daily life. Also, the clothing is placed relatively close to the IUD.

[0030] The receiving device may be a mat or a blanket. Such devices may allow for extended monitoring and / or charging, for example, while the user is lying down or sleeping.

[0031] The wearable receiving device may include a transmitter for wirelessly transmitting the received sensor data to an external device. The external device may be a portable electronic device (such as a mobile phone, tablet, or dedicated handset) or a computer. The external device may be a remote server or a database for building a library of sensor data.

[0032] The intrauterine device may have an antenna located within the intrauterine device.

[0033] The intrauterine device may have a contraceptive copper portion located on the exterior of the intrauterine device.

[0034] The contraceptive copper portion may be spatially separated from the antenna so that it does not interfere with the operation of the antenna. [Brief explanation of the drawings]

[0035] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which like parts are provided with corresponding reference numerals, and in which:

[0036] [Figure 1] 1 illustrates a schematic diagram of an intrauterine system according to an embodiment of the present invention. [Figure 1a] 1 illustrates schematically one suitable form of receiving device; [Figure 1b] 1 illustrates schematically one suitable form of receiving device; [Figure 2] 1 illustrates a schematic diagram of an IUD according to one embodiment. [Figure 3] 1 illustrates a schematic diagram of an IUD according to another embodiment. [Figure 4A] 1A and 1B schematically illustrate a front view of a wearable garment according to one embodiment. [Figure 4B] 4B schematically illustrates a rear view of the wearable garment according to the embodiment of FIG. 4A. [Figure 5] 4B shows a schematic diagram of the wearable garment of the embodiment of FIG. 4A in use. [Figure 6] 1 illustrates a schematic diagram of an inductive coupling between a sensor device and a receiving device. [Figure 7] FIG. 1 is a schematic block diagram of an implantable sensor device. [Figure 8] FIG. 2 is a more detailed schematic block diagram of an implantable sensor device. DETAILED DESCRIPTION OF THE INVENTION

[0037] Referring to Figure 1, a three-module structured multi-parameter in vivo sensing platform for intrauterine environment monitoring is shown. The platform comprises a smart IUD sensor 1 suitably shaped and dimensioned for implantation within a human uterus, an external receiver 2, and monitoring software installed on suitable data processing hardware such as a computer 3a or portable electronic device 3b.

[0038] In the present embodiment shown in Figure 1, the receiving device 2 is a wearable receiving device 2 provided on clothing, although the receiving device 2 may take any suitable form. The receiving device 2 may be a mat (e.g., as shown in FIG. 1a) or a blanket (e.g., as shown in FIG. 1b), or any other suitable means that allows long-term communication between the IUD sensor 1 and the receiving device 2.

[0039] The smart IUD sensor 1 is a fully implantable (within the uterus 5 of the human female body 6) sensor device that incorporates multiple implantable biosensors (intended to measure hormones, proteins, ions, glucose, lactate, temperature, dissolved oxygen concentration (DOC) and pH). These parameters can be monitored over time and serve as diagnostic tools. For example, oxygen depletion (determined by dissolved oxygen concentration) may indicate endometrial cancer. These cancers are often not associated with pain, so they can be detected very early. Similarly, excess estradiol may indicate endometritis.

[0040] The smart IUD sensor 1 functions as a contraceptive device. The sensor 1 functions by either chemical, physical, or a combined destruction mechanism. Regarding chemical disruption, Sensor 1 releases hormones into the uterus to disrupt the intrauterine environment. In one example, the hormone is a progestin. It works as a contraceptive method to prevent pregnancy in two ways: First, excess progestin in the uterus thickens the cervical mucus, effectively blocking sperm from reaching the egg. Second, progestins prevent the ovaries from releasing eggs. In another example, the chemical may be non-hormonal, such as copper. In this instance, copper also acts as a contraceptive by thickening cervical mucus and blocking sperm from reaching the egg. Second, copper prevents a fertilized egg from being able to implant in the uterine lining.

[0041] For chemical destruction, the sensor 1 may have a membrane coating that releases progestin, or alternatively may have a copper wire wrapped around the body of the sensor 1.

[0042] With regard to physical disruption, the sensor 1 is shaped to fit inside the uterus and contact at least a portion of the uterine lining within the uterus. This allows the sensor 1 to prevent pregnancy by preventing the growth of the uterine lining and thus affecting the successful implantation of the fertilized egg. As the uterus is typically pear-shaped, the sensor 1 may be of any suitable shape and size. For example, the shape of the sensor 1 may be T-shaped, serpentine-shaped, or elliptical. Advantageously, the shape of the sensor 1 allows it to be fixed within the uterus.

[0043] As previously mentioned, the sensor 1 can function as a contraceptive device using both chemical and physical disruptive means.

[0044] The smart IUD sensor 1 is placed outside the user's body and can wirelessly receive power from and transmit data to the wearable receiver 2 worn by the user. As a result, the smart IUD sensor 1 eliminates the need for batteries and cables and is similar in size to a standard IUD for contraception. This is important because devices must meet strict size restrictions in order to be implanted in the uterus. Some battery-based sensors have been found to be too large for use in utero. Additionally, battery-based designs are typically limited by the physical size of the battery and the short lifespan of the battery before it quickly wears out and is no longer capable of continuing operation. Additionally, there are potential risks from the toxic materials in the battery.

[0045] The receiver 2 acts as an intermediary between the IUD sensor device 1 and an external data processing device running appropriate software (thus acting as a data analysis device). In particular, receiver 2 energizes the sensor device and collects real-time information. The antenna 4 of the receiver 2 can be embedded in the clothing and wired to the receiver 2 . A software module has been developed for simultaneous uploading of in vivo data to a smart terminal or PC server for post-hoc data processing and analysis. The software module consists of a set of monitoring software running on a PC or smart terminal, which is designed to be a user-friendly interface for data processing and system configuration. The placement of the smart IUD sensor 1 within the uterus is shown in FIG. In this example, the smart IUD sensor 1 has a generally elongated structure and is positioned substantially upright (vertical) within the uterus such that the longitudinal axis of the smart IUD sensor 1 is substantially vertical when the user is standing, although it will be understood that the vertical orientation can be achieved with other shapes, such as an oval shape.

[0046] In this three-module structured system, the effectiveness of wireless energy transfer and data communication between the smart IUD sensor 1 and receiver 2 directly impacts the intended utility of the system. An optimized design can not only result in good performance, small size, low power consumption and low cost, but also improve the end-user experience and clinical practice.

[0047] Referring to FIG. 2, an example structure of the smart IUD sensor 1 is shown. In FIG. 2( a ), the top portion of the T-shaped smart IUD sensor can be seen to comprise a middle connector 20 , a first arm 21 , and a second arm 22 having a connector 23 . In FIG. 2(b), it is illustrated that the intermediate connector 20 is made of a different material having a different hardness from the joint of the first arm 21 and the second arm 22. In particular, a relatively hard material is used for the body and connector 23, while a relatively soft material is used to form the junction of the first arm 21 and the second arm 22. From Figure 2(c) it can be seen how the first arm 21 and second arm 22 are bent together during delivery into and removal from the uterus to aid in insertion / removal. Once inserted, the first arm 21 and the second arm 22 help to hold the smart IUD sensor 1 in place within the uterus. Although this embodiment uses two arms, it should be understood that other embodiments may use one arm, or more than two arms, or other shapes of smart IUD sensor 1.

[0048] In FIG. 2( d ), it can be seen that the main circuit board 24 is connected to the intermediate connector 20 , and the antenna 25 is fixed to the second arm 22 via the connector 23 . The main circuit board 24 carries the sensors and circuitry described in detail below. In this arrangement, one of the arms serves to assist in holding the smart IUD sensor 1 in place within the uterus and also functions as an antenna for communicating with (and receiving power from) receiver 2. Because the antenna 25 is generally horizontal in utero, it is particularly effective for use with a receiver having an antenna implanted in the ependyma. In alternative embodiments, the antenna may not form part of the arm, but may be located elsewhere. For example, the antenna may be in the intermediate connector portion 20 (as shown in Figure 2(e)).

[0049] The antenna is wrapped around the inside of the arm 22 or middle connector portion 20 of the IUD sensor 1 , and the IUD sensor includes a coating or material portion 26 on the body of the sensor 1 . The coating or material portion 26 contains a hormonal or non-hormonal contraceptive chemical, such as copper or a progestin, and releases the contraceptive chemical, such as copper ions or a progestin, over time. In this example, the antenna communicates with a receiving device 2 to provide sensor data, while the coating enables the sensor 1 to function as a contraceptive device. As previously mentioned, the hormonal or non-hormonal contraceptive chemicals in the coating help to prevent pregnancy by altering the intrauterine environment. The coating or material portion 26 may be in the form of a copper winding. The coating or material portion 26 is in fluid contact with physiological fluids within the uterine cavity and can provide a contraceptive function.

[0050] Placing the antenna inside the IUD is beneficial because it insulates the antenna from the physiological fluids in the uterine cavity. The physiological fluid within the uterine cavity has a high electrical conductivity, rendering the radio antenna ineffective unless the coil is insulated.

[0051] The internal antenna may be spatially separated from the contraceptive coil 26 that provides the contraceptive function, or may be located wholly or partially beneath the coil or coating that provides the contraceptive function.

[0052] Regardless of the location of the antenna relative to the IUD sensor 1, the IUD sensor may be shaped and sized to prevent pregnancy by physical disruption of the uterine lining (ie, endometrium).

[0053] Referring to FIG. 3, a simplified structure of a smart IUD sensor is shown. The left side of FIG. 3 shows a cross section of the mid-connector 32, and the right side of FIG. 3 shows the complete smart IUD sensor 30, including the internal connections of the mid-connector 32. The intermediate connector 32 has two sockets, here presented as a rectangular slot 38 for connecting to the main circuit board 36 (with the sensor and circuitry on the board), and a circular slot 39 for connecting to the tube antenna 34. As previously mentioned, the antenna 34 may be housed within the tube 34 or may be within the arm. The smart IUD sensor 30 may also include a coating on a portion of the device. For example, the coating may extend only along the intermediate connector 32 or may extend over the entire body of the device 30 . The orientation of the sensor device in Figure 3 is vertical in the uterus and is suitable for use with a receiver having a belt antenna or an antenna embedded in underwear (or a disposable sanitary napkin). It will be appreciated that the sensor device of FIG. 3 may, if desired, include one or more arms to assist in stabilizing its position within the uterus, or may have any other suitable shape. Compared to other antenna types, tube antennas do not require a coil frame, so they can be relatively small and tightly wound on a ferrite core. Considering the complexity of fabrication and the need to make the sensor as small as possible, a tube antenna with a ferrite core is believed to be a particularly suitable antenna for implantable sensor devices. The antenna 34 may be a single axis antenna formed as a coil antenna wound on a core such that the wire is disposed circumferentially around only one axis of the core.

[0054] FIG. 4A shows a receiver 2 in the form of a wearable garment, in this case underwear 40, that includes Helmholtz coils. The front view is shown. The underwear 40 includes a first Helmholtz coil 42 a disposed at the front of the underwear 40 . The first Helmholtz coil 42a is positioned to substantially conform to the contours of the wearer's body when worn, such as along the groove where the user's legs join the pelvis. FIG. 4B shows a rear view of the undergarment 40. The underwear 40 includes a second Helmholtz coil 42b disposed on the back of the underwear 40.

[0055] Each Helmholtz coil is a generally planar wound wire that is protected from moisture ingress by a moisture seal barrier, such as by sandwiching the wire between two moisture seal layers. Typically, a Helmholtz coil comprises copper tracks mounted on a polyimide film.

[0056] FIG. 5 shows the underwear 40 being worn by a user. The user also implants an IUD sensor 1 in the uterus as described above. The IUD sensor 1 has a single-axis antenna. As previously mentioned, the underwear 40 includes the first Helmholtz coil 42a and the second Helmholtz coil 42b disposed on the front and back of the underwear 40, respectively. The coils 42a, 42b are arranged such that the first Helmholtz coil 42a is located on a first side of the single-axis antenna 34 and the second Helmholtz coil 42b is located on a second side of the single-axis antenna 34. It can be understood that the first Helmholtz coil 42a is positioned on a first side of the garment and the second Helmholtz coil 42b is positioned on a second side of the garment, so that when the garment is worn by a user, the first Helmholtz coil 42a is positioned on the opposite side of the user from the second Helmholtz coil 42b.

[0057] Each Helmholtz coil 42a, 42b defines a respective major axis 44a, 44b that extends through the center of the coil and perpendicular to the plane of the coil. As can be seen, the major axes 44 a , 44 b of the two Helmholtz coils 42 a , 42 b substantially intersect at the location of the IUD sensor 1 . Thus, when a current is passed through the Helmholtz coils, a highly uniform magnetic field is generated between them, within which the IUD sensor 1 is placed. The IUD sensor 1 can therefore be wirelessly charged from this magnetic field using its single axis antenna.

[0058] The direction of current in each of the coils can be applied in the same direction, clockwise or counterclockwise, through both the front and back coils when viewed from the front of the body, generating a magnetic field that is essentially aligned with the sensor's single axis antenna located between the transverse planes of the body and close to, but not aligned with, the frontal plane of the body. Alternatively, the direction of current in each of the coils can be applied in a different direction through the frontal coil relative to the back coil, generating a magnetic field that essentially coincides with the sensor's single axis antenna coinciding with the frontal plane of the body. This provides the ability to generate a properly oriented magnetic field depending on the orientation of the single axis antenna. This orientation will likely depend on the orientation of the uterus in which the device is implanted, and it is typically not possible to change this orientation in vivo. It is therefore important to be able to control the direction of the applied magnetic field in the manner described.

[0059] Referring to FIG. 6, a setup is shown illustrating how the receiver 2 and IUD sensor 1 can be expected to communicate and transfer power. In FIG. 4, power generated by AC power source 41 is transferred from receiver 2 to inductively coupled IUD sensor 1 using energy in an alternating magnetic field generated by receiver 2. The power transfer in Figure 4 is achieved by the principle of magnetic induction, and both the wireless power transfer to the IUD sensor 1 and the communication between the two devices are achieved using the same near-field magnetic induction link.

[0060] The receiver 2 drives the primary coil 43 at low frequency to generate a magnetic field (in this case at a frequency of the order of 100 kHz). The IUD sensor 1 has a secondary coil 45 in proximity to a primary (receiver) coil 43, which is inductively coupled to the receiver coil 43 (via a magnetic field H). This results in an induced voltage across the IUD sensor coil 45 which is then converted to energy by the front end 47 to power the integrated circuit 46 of the IUD sensor 1 . More specifically, the front end 47 can use the energy received at the coil 45 to charge a capacitor 48 , which can then be used to power the sensor circuitry 46 . To allow for high power transfer efficiency over distance, both the receiver 2 and the IUD sensor 1 are preferably designed to operate their antenna circuits at the same resonant frequency.

[0061] Communication between the receiver 2 and the IUD sensor 1 is achieved using the same pair of coils 43, 45 that power the IUD sensor 1. When the receiver or IUD sensor 1 manipulates the applied voltage to change the amplitude, frequency or phase of the voltage on one side, the other side detects a similar change via the inductive link between the two devices. A message is encoded in this variation, and how fast the message can be sent, or data rate, depends on the bandwidth of this inductive link. Any form of modulation (amplitude, frequency, or phase) creates sidebands in the frequency domain that make detection of the modulated signal difficult or impossible if the frequency spectrum of the modulated signal does not fall entirely or substantially within the bandwidth of the inductive link. In this embodiment, the message sent from receiver 2 to IUD sensor 1 via the inductive link may be a command message that triggers IUD sensor 1 to take (for example) a sensor measurement, while the message sent from IUD sensor 1 to receiver 2 via the inductive link may be (for example) sensor data generated by a pH sensor, temperature sensor or dissolved oxygen sensor, or a status message indicating the current state of IUD sensor 1 (for example, power level).

[0062] Referring to FIG. 7, a block diagram of a suitable microsystem architecture for the IUD sensor 1 is shown. To achieve data capture, signal processing and wireless communication, the microsystem comprises an integrated sensor or multi-sensor array 51, analog signal conditioning circuitry 52, an analog-to-digital converter (ADC) 53 optionally including a multiplexer (MUX), a digital signal processor 54 or microprogrammed control unit (MCU), a wireless transmitter 55 and a power manager 56. In operation, the sensor 51 converts a physical parameter into an electronic signal. The sensors can be fabricated on small silicon chips based on microfabrication techniques suitable for microsystems. Conditioning circuit 52 is used to improve the quality of the analog signal from sensor 51 . Generally, higher end regulation performance requires more complex circuitry. Simpler conditioning circuits require additional data processing after analog-to-digital conversion, limiting performance. Therefore, a balance between signal conditioning performance and circuit complexity should be considered for system implementation. A multiplexer (MUX) may be utilized for hardware sharing of the circuitry, which has the advantage of reducing the size and power consumption of the device. Processor 54 provides logic control and digital signal processing. Microprogrammed control units (MCUs) are widely used components due to their flexible functions and excellent expandability. At the same time, compared to powerful processors, MCUs can reduce power consumption. A radio transmitter 55 and a power manager 56 are provided for data transmission and power control, respectively. The integration of these different units can facilitate miniaturization of the device.

[0063] Referring to Figure 8, the main structure of IUD sensor 1 is shown in more detail, comprising sensors 61a, 61b, 61c (in each case hormones, proteins, glucose, lactate, ions, temperature, DOC and pH), respective analog signal conditioning units 62a, 62b, 62c (for conditioning the output of each of sensors 61a, 61b, 61c), multiplexer 63a (to allow the array of sensors to be interfaced with an ADC), analog to digital converter 63b and MCU 64, and transmitter 65. For example, bidirectional communication with the MCU from outside the body is also possible to wake the MCU from a power-saving sleep state. Additionally, the antenna can be used for wireless power transfer via inductive coupling. Here, the transmitter 65 comprises a passive RF control unit 65a for communicating with the MCU 64 and for controlling an antenna driving circuit 65b and a charging circuit 65c. The antenna driving circuit is capable of two-way data communication with an external receiver (antenna, ANT) via an antenna (loop antenna in this case) 68, and also receives power (charging voltage, VCL) via the antenna 68. It will therefore be appreciated that the system utilizes wireless power transfer by inductive coupling using low frequency RFID signals to transmit data and receive power through the abdominal region of the user. The charging circuit 65c charges the capacitor 67 and can also power the control unit 65a using power received via the antenna 68 and the drive circuit 65b. All power is managed through the power management block 66 . The flow of power around the circuit in Figure 8 is indicated by solid directional arrows. The flow of analog data signals is indicated by a first type of dashed directional arrow. The flow of control signals is indicated by a second type of dashed directional arrow. Data flow is indicated by solid block arrows. It can be seen that the charging capacitor 67 supplies power to the power manager 66 (which in turn manages the power supply to the multiplexer 63a, the ADC 63b and the MCU 64), and to the signal conditioning units 62a, 62b, 62c. Capacitor 67 is preferably a ceramic capacitor. This type of capacitor is particularly suitable for this purpose for safety reasons, for example, because it does not utilize toxic substances and there is little or no risk of leakage.

[0064] The receiving device has a primary coil for wirelessly communicating with the IUD sensor, and the quality factor of the primary coil is controllable to be higher when the receiving device is wirelessly charging the IUD sensor than when the receiving device is receiving sensor data from the IUD sensor.

[0065] As a result of the controllable quality factor, the same coil can be used for both efficient power transfer (wireless charging) by using the coil in a (relatively) high quality factor mode, and reliable data communication by using the coil in a (relatively) low quality factor mode.

[0066] By varying the electrical resistance associated with the primary coil, the quality factor may be controllable. For example, a damping resistor can be switched in and out of series with the primary coil.

[0067] The quality factor of the primary coil may be selectable between a number of different levels. In a simple case, this could be two levels: a high level for wireless charging and a low level for receiving and / or transmitting data. In more complex cases, this could be, for example, three levels with an intermediate quality factor where different quality factors are optimal for transmitting data compared to receiving data. For example, different data rates may be used for transmission and reception. If a higher data rate is used for reception, the quality factor will be lower since reception requires a higher bandwidth. Another reason for providing multiple different quality factors is to provide robustness to the communication link when the user is in close proximity to a metallic environment. For example, if a user is sitting in a car or sitting on a metal chair, and the system is operating at a high quality factor, the presence of the metal may detune the system, causing power transfer and / or communication to fail. However, a system with a lower quality factor will waste more power, which is generally undesirable and may be unacceptable for receiving devices that require relatively low power consumption. To alleviate this problem, the system can be configured to adaptively change the quality factor to accommodate the external environment while maintaining reasonable battery life.

[0068] The receiving device 2 may have a user interface including an LCD display and keyboard to display the received sensor data and system information provided by the microcontroller, and may provide functionality for a user to operate the device, again via the microcontroller. The Bluetooth module can provide high-level communication with a server or smart terminal and can perform data analysis.

[0069] The IUD sensor may be operable for single sampling or continuous sampling. The IUD may be wirelessly charged from the receiving device in multiple steps per sampling event, or alternatively, the IUD sensor may be charged on demand such that the IUD is wirelessly charged from the receiving device whenever the IUD's charge level falls below a threshold.

[0070] The low power state may be a "sleep" state in which the device is essentially powered down to conserve power, but is able to wake up to operate. In contrast, the idle state may be an operating state in which the device is simply waiting for instructions. A device can respond faster when it is idle than when it is in a low-power (sleep) state.

[0071] As mentioned above, electromagnetic induction wireless transmission technology is used for near-field energy transmission through the use of two coupled coils, a primary coil and a secondary coil, provided in the receiving device and the implantable IUD sensor, respectively. Current flowing through the primary coil creates a magnetic field that acts on the secondary coil, generating an induced current therein. Tight coupling is required for high energy recovery efficiency and long working distance. Increasing the distance between the coils causes the magnetic field to extend beyond the receiving area of ​​the secondary coil, leading to a loss of transmitted energy. For its intended use, the implantable IUD sensor requires small size, low power consumption, and a relatively short operating distance of approximately 10 cm. This allows for long-term monitoring of intrauterine parameters. If the IUD sensor 1 uses a hormonal coating, ideally the sensor is replaced after the hormonal coating is depleted. Typically, this can be between 3 and 7 years after implantation.

[0072] Energy loss due to tissue absorption of the radio signal (electromagnetic energy is converted into other forms of energy, such as heat, by substances within the tissue medium) depends on the signal frequency. Lower frequency signals have better propagation characteristics and less tissue absorption. Therefore, implantable IUD sensors utilize wireless energy transfer based on low frequency electromagnetic induction. The circuitry for wireless energy transfer can also function as a low frequency RFID link for wireless data communication, reducing the need for additional circuitry or board space for data communication. In the intended application, the in-vivo information and system configuration do not require high data rate transmission, and the LF RFID link can provide sufficient data bandwidth to meet the requirements. This means that the data communication range is typically farther than the energy transmission distance, so it is not a bottleneck for the effective operating distance.

[0073] By monitoring changes in biophysical parameters within the uterus, the IUD sensor 1 can be used to diagnose conditions.

[0074] Although the various technologies and implantable IUD sensors and external receivers have been described in the context of intrauterine monitoring, it will be appreciated that these technologies and structures may also be applied to monitoring other body cavities, such as within the vagina, bladder, or gastrointestinal tract of a human or animal body.

Claims

1. an intrauterine device shaped and dimensioned for implantation within the uterus; With an external receiving device An intrauterine system comprising: the intrauterine device is for measuring conditions within the uterus to generate sensor data and for functioning as a contraceptive device to prevent pregnancy; The intrauterine system, wherein the receiving device is for wirelessly receiving the sensor data generated by the intrauterine device.

2. The intrauterine system of claim 1 , wherein the receiving device is operable to wirelessly charge an implantable sensor device.

3. 3. The intrauterine system of claim 1 or 2, wherein the intrauterine device is shaped to be anchored within the uterus.

4. The intrauterine system of any one of claims 1 to 3, wherein the intrauterine device is shaped to contact at least a portion of the uterine lining within the uterus.

5. 5. The intrauterine system of claim 4, wherein at least a portion of the intrauterine device in contact with the uterine lining prevents pregnancy by impeding growth of the uterine lining to affect implantation of a fertilized egg.

6. The intrauterine system according to any one of claims 1 to 5, wherein the intrauterine device releases chemicals into the uterus to disrupt the environment within the uterus.

7. 7. The intrauterine system of claim 6, wherein the chemical is provided within or as a coating on a portion of the intrauterine device, or within or as part of the intrauterine device.

8. 8. An intrauterine system according to claim 6 or claim 7, wherein the chemical substance is hormonal or non-hormonal, preferably one or more of copper, progestin or estrogen.

9. 9. The intrauterine system of any one of claims 1 to 8, wherein the receiving device comprises an antenna, a transceiver circuit and a power source, and the intrauterine device comprises an antenna, a charging circuit and a controller, the receiving device operable to transfer power from the antenna of the receiving device to the antenna of the intrauterine device via electromagnetic coupling, the power being used by the charging circuit to store power for operating the sensor of the intrauterine device and for transmitting sensor data to the receiving device.

10. 10. The intrauterine system of claim 9, wherein the intrauterine device comprises a capacitor or a rechargeable battery, and the charging circuit stores the power by charging the capacitor or the rechargeable battery.

11. 11. The intrauterine system of claim 9 or claim 10, wherein the power source is a rechargeable battery.

12. the receiving device has a controller and a primary coil for wirelessly communicating with the intrauterine device, the receiving device being operable to wirelessly charge the intrauterine device via inductive coupling between the primary coil and a secondary coil; the quality factor of the primary coil is controllable; the controller is operable to control the quality factor of the primary coil so that the quality factor is higher when the receiving device is wirelessly charging the intrauterine device than when the receiving device is receiving sensor data from the intrauterine device; An intrauterine system according to any one of claims 1 to 11, wherein the receiving device drives the primary coil to operate at a frequency of the order of 100 kHz.

13. 13. The intrauterine system of any one of claims 1 to 12, wherein the intrauterine device comprises a single-axis antenna and the receiving device comprises a Helmholtz coil, the Helmholtz coil being arranged to communicate with the single-axis antenna to wirelessly charge the intrauterine device and to receive the sensor data.

14. 14. An intrauterine system according to claim 13, wherein said single axis antenna is adapted to operate at a frequency in the range of 119 kHz to 140 kHz, preferably 130 kHz to 140 kHz, preferably 139.6 kHz.

15. An intrauterine system according to any preceding claim, wherein the intrauterine device comprises one or more of a temperature sensor, a pH sensor and a dissolved oxygen sensor.

16. An intrauterine system according to any one of claims 1 to 15, wherein the intrauterine device comprises one or both of an electrical conductivity sensor and a pressure sensor.

17. 17. The intrauterine system of any one of claims 1 to 16, wherein the intrauterine device comprises a body and one or more arms, the arms projecting laterally from the body for securing the sensor within the uterus.

18. 18. The intrauterine system of claim 17, wherein the intrauterine device comprises a pair of arms positioned at or adjacent one end of the body and extending generally away from each other.

19. An intrauterine system according to any one of claims 1 to 18, wherein the receiving device is a wearable receiving device.

20. An intrauterine system according to any one of claims 1 to 19, wherein the receiving device is provided on a garment.

21. 21. The intrauterine system of claim 20, wherein the garment is underwear worn adjacent to the uterus.

22. The intrauterine system according to any one of claims 1 to 18, wherein the receiving device is a mat or a blanket.

23. An intrauterine system according to any one of claims 1 to 22, wherein the receiving device comprises a transmitter for wirelessly transmitting received sensor data to an external device.

24. 24. The intrauterine system of claim 23, wherein the external device is a portable electronic device or a computer.

25. An intrauterine system according to any one of claims 1 to 24, wherein the intrauterine device has an antenna located inside the intrauterine device.

26. 26. The intrauterine system of claim 25, wherein the intrauterine device comprises a contraceptive copper portion located externally to the intrauterine device.

27. 27. The intrauterine system of claim 26, wherein said contraceptive copper portion is spatially separated from said antenna so as not to interfere with the operation of said antenna.

Images