Prediction system for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section and its construction method

Abstract

The present invention belongs to the field of biomedicine, and relates to an obstetric surgery risk prediction system, and specifically to a prediction system for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section and a construction method thereof. The prediction system for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section includes a variable input module and a nomogram model prediction module; the variable input module is used to input variables of the maximum diameter of the gestational sac, the number of cesarean sections, the medical history of uterine incision pregnancy, the distance between the gestational sac and the uterine incision scar, and the variable of the yolk sac visible by ultrasound; by substituting the values ​​of each variable into the nomogram model prediction module, the probability value of the risk of surgical bleeding can be obtained, which provides a reliable and effective reference for the configuration of obstetric surgery resources, and increases the investment in physical therapy resources for patients with higher bleeding risks. This scheme can solve the technical problem that the existing technology lacks a prediction system for the risk of massive bleeding during artificial abortion of unexpected pregnancy after cesarean section, and has an ideal prospect for application and promotion.

Description

Technical Field

[0001] The present invention belongs to the field of biomedicine and relates to an obstetric surgery risk prediction system, and specifically to a system for predicting massive bleeding during artificial abortion for unexpected pregnancy after cesarean section and a construction method thereof. Background Art

[0002] Although the maternal mortality rate related to artificial abortion is relatively low, the long-term abnormally high cesarean section rate has resulted in a large number of people with scarred uteruses, which has increased the risk of artificial abortion. The current population generally has a weak awareness of contraception and lacks contraceptive knowledge, which has led to a high proportion of accidental pregnancies after cesarean sections. Compared with ordinary abortions, the surgical risks related to maternal death, such as intraoperative hemorrhage and uterine perforation, are significantly increased when artificial abortions are performed on this group of people. Predicting the risk level of heavy bleeding during abortions in advance will help reduce maternal mortality and ensure medical safety.

[0003] The inventors first studied 228 patients who were scheduled to undergo artificial abortion for unplanned intrauterine pregnancy after cesarean section (Wen Yu, Analysis of high-risk factors for massive bleeding during artificial abortion for unplanned pregnancy after cesarean section, Journal of Chongqing Medical University, Vol. 48, No. 11, 2023), and found that five factors, including the number of cesarean sections, the maximum diameter of the gestational sac, the distance of the gestational sac from the uterus, the distance of the uterine incision scar, embryonic arrest, and pregnancy time, were independent risk factors for massive bleeding during artificial abortion for unplanned intrauterine pregnancy after cesarean section. The reason for the analysis is that the larger the chorionic implantation area, the deeper the chorionic implantation, the higher the thickness of the decidua, and the closer the relationship between the tissue and the uterine myometrium after embryonic arrest, and even adhesion. During the operation, it is difficult to aspirate the embryonic sac and decidual tissue in the uterine cavity, the operation time is relatively increased, the blood sinus of the embryonic implantation tissue closes slowly, and the uterine cavity accumulates a lot of blood, which is not conducive to uterine contraction, resulting in massive bleeding. However, how can the above risk factors be used to predict the risk of massive bleeding during artificial abortion for unexpected pregnancy after cesarean section? How effective are the above risk factors in predicting the risk of massive bleeding? These problems have not yet been effectively solved. It is urgent to further study the risk factors for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section, establish an effective risk prediction system, and then predict the risk level of massive bleeding during artificial abortion in advance to ensure medical safety. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a system for predicting the risk of massive bleeding during artificial abortion of unexpected pregnancy after cesarean section, so as to solve the technical problem that the prior art lacks a system for predicting the risk of massive bleeding during artificial abortion of unexpected pregnancy after cesarean section. The prediction system of this scheme is constructed through epidemiological analysis and statistical modeling of a large amount of clinical data. The system can accurately evaluate and predict whether patients with artificial abortion of unexpected pregnancy after cesarean section will experience severe bleeding, so as to adopt reasonable surgical resource allocation, ensure medical safety, and avoid waste of medical resources.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A system for predicting massive bleeding during artificial abortion of unexpected pregnancy after cesarean section, including a variable input module and a nomogram model prediction module;

[0007] The variable input module is used to input a variable of the maximum diameter of the gestational sac, a variable of the number of cesarean sections, a variable of a history of pregnancy with uterine incision, a variable of the distance between the gestational sac and the uterine incision scar, and a variable of a yolk sac visible by ultrasound;

[0008] The variable of maximum diameter of gestational sac is the measured value of the maximum diameter of gestational sac, in cm;

[0009] The variable of the number of cesarean sections was referred to as 1 or 2; 1 represented 1 cesarean section and 2 represented ≥ 2 cesarean sections;

[0010] The variable of hysterotomy pregnancy history was represented by 0 or 1; 0 represented no previous hysterotomy pregnancy, and 1 represented previous hysterotomy pregnancy;

[0011] The variable of the distance between the gestational sac and the uterine incision scar is represented by 0, 1 or 2; 0 means that the distance between the gestational sac and the uterine incision scar is 0-1 cm, 1 means that the distance between the gestational sac and the uterine incision scar is greater than 1 and less than or equal to 2 cm, and 2 means that the distance between the gestational sac and the uterine incision scar is greater than 2 cm.

[0012] The variable of ultrasound-visible yolk sac is represented by 0 or 1; 0 represents ultrasound-visible yolk sac, and 1 represents ultrasound-unvisible yolk sac;

[0013] The nomogram model prediction module is as follows Figure 1 shown.

[0014] The nomogram model prediction module includes a scoring scale, a variable line segment combination and an evaluation scale combination;

[0015] The variable line segment combination consists of five variable line segments established according to the variables of the maximum diameter of the gestational sac, the number of cesarean sections, the history of pregnancy with uterine incision, the distance between the gestational sac and the uterine incision scar, and the variable of the yolk sac visible on ultrasound. The variable line segments are marked with scales representing the variable values.

[0016] The evaluation scale combination consists of a total score scale and a surgical blood loss risk scale;

[0017] The variable value is matched to the corresponding point on the variable line segment, and then the point is used as a vertical line of the variable line segment to correspond to the scoring scale above to obtain the score of the variable; the scores of the five variables are summed to obtain the total score; the total score value is matched to the corresponding point on the total score scale, and then the point is used as a vertical line of the total score scale to correspond to the surgical bleeding risk scale below to obtain the probability value of the patient's surgical bleeding risk. Among them, the probability value range is 0-1.

[0018] Furthermore, in the variable segment representing the number of cesarean sections, when the number of cesarean sections variable takes a value of 1, the corresponding score on the scoring scale is 0; when the number of cesarean sections variable takes a value of 2, the corresponding score on the scoring scale is 67.5.

[0019] Furthermore, in the variable segment representing the variable of hysterotomy pregnancy history, when the variable value of hysterotomy pregnancy history is 0, the corresponding score on the scoring scale is 0; when the variable value of hysterotomy pregnancy history is 1, the corresponding score on the scoring scale is 75.

[0020] Furthermore, in the variable segment representing the variable of the distance from the gestational sac to the uterine incision scar, when the variable value of the distance from the gestational sac to the uterine incision scar is 0, the corresponding score on the scoring scale is 30; when the variable value of the distance from the gestational sac to the uterine incision scar is 1, the corresponding score on the scoring scale is 11; when the variable value of the distance from the gestational sac to the uterine incision scar is 2, the corresponding score on the scoring scale is 0.

[0021] Furthermore, in the variable segment representing the variable of ultrasound-visible yolk sac, when the variable value of ultrasound-visible yolk sac is 0, the corresponding score on the scoring scale is 44; when the variable value of ultrasound-visible yolk sac is 1, the corresponding score on the scoring scale is 0.

[0022] Furthermore, in the variable line segment representing the variable of the maximum diameter of the gestational sac, when 0 < the variable value of the maximum diameter of the gestational sac ≤ 9, 0 < the score on the corresponding scoring scale ≤ 100. That is, the score of the variable of the maximum diameter of the gestational sac is: (100 / 9) × the variable value of the maximum diameter of the gestational sac.

[0023] Furthermore, it also includes a judgment module, which is used to compare the probability value of the surgical bleeding risk with a set threshold; when the probability value of the surgical bleeding risk is greater than the set threshold, the system sends an alarm signal to medical staff.

[0024] The principle and beneficial effects of this technical solution are:

[0025] The inventor collected a large number of cases, screened out patients who were eligible for artificial abortion due to unexpected pregnancy after cesarean section, collected basic information of the patients, clinical information of this pregnancy, and ultrasound imaging information of the gestational sac of this pregnancy, and obtained 7 risk factors after analyzing all test variables by univariate method, and used logistic regression to determine 5 independent risk factors for the 7 risk factors. The independent risk factors were introduced into R software, and the RMS package was used to construct a nomogram model for predicting the occurrence of massive bleeding during artificial abortion, and then a prediction system for massive bleeding during artificial abortion due to unexpected pregnancy after cesarean section was constructed.

[0026] In order to verify the predictive effectiveness of this system, a test experiment of the system effectiveness was conducted. The test results showed that this system has high sensitivity, specificity and accuracy. The area under the curve is 0.889, the sensitivity and specificity are 91.50% and 70.50% respectively, and the verification results show that the model has good discrimination. It can be seen that this system can accurately predict and evaluate whether patients with artificial abortion surgery for unexpected pregnancy after cesarean section will experience severe bleeding. Medical staff can take certain measures to prevent it according to the high-risk degree and risk of morbidity, and try to improve the adverse outcomes of artificial abortion.

[0027] The five independent risk factors used in this scheme include the maximum diameter of the gestational sac, the number of cesarean sections, the history of uterine incision pregnancy, the distance between the gestational sac and the uterine incision scar, and the visible yolk sac on ultrasound. In particular, the factor of visible yolk sac on ultrasound is the first independent risk factor found in this study to affect the bleeding situation of artificial abortion surgery for unexpected pregnancy after cesarean section. The prior art generally believes that embryonic arrest and pregnancy time are factors that affect bleeding. However, in this study, the above risk factors are excluded, a more accurate evaluation model is established, and the false positive prediction situation is reduced. In the prior art, before medical staff perform obstetric surgery, surgical resources (manpower, material resources, etc.) are basically based on B-ultrasound results. After long-term research and practice, the inventor found that the risk assessment factors used in the past are not completely applicable. This system uses five key risk factors to predict the risk of bleeding in artificial abortion, which can predict risks more scientifically and allocate appropriate surgical resources to prevent waste of manpower and material resources.

[0028] In summary, this system has high sensitivity, specificity and accuracy. The risk factor variables included in this system are all objective variables, which reduces the result deviation caused by uneven professional levels of clinicians. This scheme incorporates new risk factors (for example: ultrasound visible yolk sac), which can perform risk assessment more accurately. The technical scheme of the present invention overcomes the technical bias in the prior art, excludes the factors of embryonic arrest and pregnancy time from this system, improves the accuracy of this system, and can better provide reference for clinicians. This system provides a reliable and effective reference for the configuration of obstetric surgical resources. Medical staff can configure surgical resources according to the risk value and invest more manpower and material resources in patients with higher bleeding risks. For patients with lower bleeding risks, there is no need to invest too many surgical resources, which plays a role in rationally allocating medical resources and reducing the waste of medical resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The invention discloses a nomogram prediction model for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section.

[0030] Figure 2 The present invention is a calibration curve of the nomogram model for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section.

[0031] Figure 3 The present invention provides a nomogram ROC curve for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following examples and experimental examples are conventional means well known to those skilled in the art, and the materials, reagents, etc. used can be obtained from commercial sources.

[0033] Example

[0034] 1. Materials and methods

[0035] 1.1 Study subjects and inclusion criteria

[0036] A total of 224 patients who underwent artificial abortion after unexpected pregnancy after cesarean section in the Department of Obstetrics and Gynecology of ×××× Hospital from January 2022 to March 2023 were selected as the research subjects. 68 patients had intraoperative blood loss ≥ 200 mL.

[0037] (1) Inclusion criteria: ① A history of one or more cesarean sections; ② The current pregnancy was unplanned; ③ The gestational age at the time of artificial abortion was less than 10 weeks; ④ B-ultrasound confirmed intrauterine pregnancy without ectopic pregnancy; ⑤ No serious internal or surgical complications that would affect the implementation of surgery and anesthesia; ⑥ No acute systemic or genital inflammation; ⑦ No uterine dysplasia or abnormal uterine cavity morphology due to uterine fibroids that would affect the implementation of surgery; ⑧ The consent form for surgery was complete.

[0038] (2) Exclusion criteria: ① Cesarean scar pregnancy (CSP); ② pregnancy of 10 weeks or more; ③ patients with severe internal or external diseases or genital inflammation, malformation, tumor, or mental illness who are not suitable for outpatient surgery; ④ patients who need hospitalization for surgery due to abnormal uterine morphology.

[0039] 1.2 Research Methods

[0040] 1.2.1 Diagnostic criteria

[0041] Artificial abortion refers to the operation of artificial termination of pregnancy within 14 weeks of pregnancy due to illness, unplanned pregnancy, etc. It is a remedial method after contraceptive failure. It can be divided into vacuum aspiration (6-10 weeks of pregnancy) and forceps curettage (10-14 weeks of pregnancy). This study draws on the relevant discussion of the family planning volume of the "Clinical Diagnosis and Treatment Guidelines and Technical Operation Specifications". Bleeding exceeding 200mL within 10 weeks of pregnancy is defined as heavy bleeding during artificial abortion. The statistics of intraoperative bleeding volume are completed by combining the blood collection pad weighing method and the suction bottle collection method. The time limit of laboratory test results in this study is defined as within 2 weeks before surgery.

[0042] 1.2.2 Data Collection

[0043] A data collection form for information on massive bleeding during artificial abortion during unexpected pregnancy after cesarean section was designed, which included the following content to collect the data needed for this study.

[0044] 1.2.2.1 Basic information of pregnant women: age, marital status, place of residence, educational level, body mass index before pregnancy, number of pregnancies, number of parities, number of miscarriages, previous delivery history (vaginal delivery and hospital level, cesarean section and hospital level, surgical complications, history of placenta previa, history of postpartum hemorrhage, history of postpartum placenta retention and uterine curettage), previous miscarriage history (previous abortion method, previous abortion process, previous abortion bleeding history, previous post-abortion infection, post-abortion menstruation, whether there was a previous incisional pregnancy), history of uterine surgery, etc.

[0045] 1.2.2.2 Clinical information of the current pregnancy: whether assisted reproduction was used, whether the current pregnancy was complicated by internal or external diseases, whether the woman was breastfeeding, time since the last cesarean section, time since the last natural birth, HGB (g / L) before abortion, platelet count before abortion, time of amenorrhea, whether there was vaginal bleeding, whether there was lower abdominal pain, whether the embryo had arrested development, etc.

[0046] 1.2.2.3 Ultrasound imaging information of the gestational sac of this pregnancy: maximum diameter of the gestational sac (cm), whether the yolk sac is visible, whether there is fetal heart tube pulsation, the distance between the gestational sac and the uterine incision scar (cm), etc.

[0047] 1.2.2.4 Outcome of this pregnancy termination: method of termination, whether it is painless, amount of bleeding during the operation, etc.

[0048] 1.3 Statistical analysis

[0049] SPSS23.0 software was used for statistical analysis. The measurement data (age, gestational sac diameter, etc.) were all in accordance with normal distribution and expressed as mean ± standard deviation, and the inter-group comparison was tested. The count data (cesarean section history, previous uterine incision pregnancy history, etc.) were expressed as frequency, and the inter-group comparison was tested. The variables with statistically significant clinical data comparison results (P < 0.05) were included in the multivariate regression model and analyzed to determine the independent risk factors for massive bleeding during artificial abortion. The independent risk factors were introduced into R software, and the RMS package was used to construct a nomogram model for predicting massive bleeding during artificial abortion; the receiver operating characteristic (ROC) curve was drawn, and the area under the curve was calculated; the calibration curve was drawn to evaluate the calibration of the nomogram model for predicting massive bleeding in artificial abortion after cesarean section. P < 0.05 indicated statistically significant differences.

[0050] 2. Results

[0051] 2.1 General Information

[0052] A total of 224 patients with unexpected pregnancy after cesarean section who underwent artificial abortion in the Obstetrics and Gynecology Clinic of ×××× Hospital from January 2022 to March 2023 were collected, of which 68 patients had intraoperative bleeding greater than 200 ml, accounting for 30.36%.

[0053] 2.2 Univariate analysis of intraoperative hemorrhage in patients with unexpected pregnancy and induced abortion after cesarean section

[0054] The univariate analysis of 34 research variables in the control group and the case group initially screened out that the maximum diameter of the gestational sac, the number of births, the number of cesarean sections, the history of pregnancy through uterine incision, the distance between the gestational sac and the uterine incision scar, the history of embryonic arrest, and the visible yolk sac on ultrasound were risk factors for massive bleeding during artificial abortion in unexpected pregnancy after cesarean section (P < 0.05), see Table 1.

[0055] Table 1: Univariate analysis of the risk of massive bleeding during artificial abortion in unexpected pregnancy after cesarean section

[0056]

[0057]

[0058]

[0059] 2.2 Multifactorial analysis of massive bleeding during artificial abortion during unexpected pregnancy after cesarean section

[0060] The results of multivariate logistic regression analysis of the above-mentioned 7 statistically significant factors showed that the maximum diameter of the gestational sac, the number of cesarean sections, the history of uterine incision pregnancy, the distance between the gestational sac and the uterine incision scar, and the visible yolk sac on ultrasound were independent risk factors for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section (P < 0.05). See Table 2.

[0061] Table 2: Multivariate analysis of intraoperative bleeding in unexpected pregnancy and artificial abortion after cesarean section

[0062]

[0063] 2.3 Nomogram prediction model for massive bleeding during artificial abortion in unexpected pregnancy after cesarean section

[0064] The nomogram prediction model was established based on the results of multivariate logistic regression analysis. The independent risk factors shown in Table 2 were introduced into R software, and the RMS package was used to construct a nomogram model for predicting the occurrence of massive bleeding during artificial abortion (see Figure 1 ). The method of constructing the nomogram adopts the conventional method of existing technology, and the key factor in establishing the model lies in the establishment of 5 independent risk factors.

[0065] The nomogram model includes a scoring scale, a variable segment combination, and an evaluation scale combination. The variable segment combination consists of five variable segments established according to the variables of the maximum diameter of the gestational sac, the number of cesarean sections, the history of pregnancy with uterine incision, the distance between the gestational sac and the uterine incision scar, and the variable of the yolk sac visible on ultrasound. The variable segments are marked with scales representing the variable values.

[0066] The variable of maximum diameter of gestational sac is the measured value of the maximum diameter of gestational sac, in cm, represented by integers from 1 to 9. In the variable line segment representing the variable of maximum diameter of gestational sac, when the variable of maximum diameter of gestational sac takes the value of integers from 1 to 9, the corresponding scores on the scoring scale are integers from 10 to 90.

[0067] The variable of the number of cesarean sections is represented by 1 or 2, where 1 represents 1 cesarean section and 2 represents ≥ 2 cesarean sections. In the variable line segment representing the variable of the number of cesarean sections, when the variable value of the number of cesarean sections is 1, the corresponding score on the scoring scale is 0; when the variable value of the number of cesarean sections is 2, the corresponding score on the scoring scale is 67.5.

[0068] The variable of hysterotomy pregnancy history is represented by 0 or 1, where 0 represents no previous hysterotomy pregnancy and 1 represents previous hysterotomy pregnancy. In the variable line segment representing the variable of hysterotomy pregnancy history, when the variable of hysterotomy pregnancy history is 0, the corresponding score on the scoring scale is 0; when the variable of hysterotomy pregnancy history is 1, the corresponding score on the scoring scale is 75.

[0069] The variable of the distance between the gestational sac and the uterine incision scar is represented by 0, 1 or 2; among them, 0 represents that the distance between the gestational sac and the uterine incision scar is 0-1cm, 1 represents that the distance between the gestational sac and the uterine incision scar is greater than 1 and ≤2cm, and 2 represents that the distance between the gestational sac and the uterine incision scar is greater than 2cm. In the variable line segment representing the distance between the gestational sac and the uterine incision scar, when the variable value of the distance between the gestational sac and the uterine incision scar is 0, the corresponding score on the scoring scale is 30; when the variable value of the distance between the gestational sac and the uterine incision scar is 1, the corresponding score on the scoring scale is 11; when the variable value of the distance between the gestational sac and the uterine incision scar is 2, the corresponding score on the scoring scale is 0.

[0070] The variable of ultrasound-visible yolk sac is represented by 0 or 1, where 0 represents ultrasound-visible yolk sac and 1 represents ultrasound-unvisible yolk sac. In the variable line segment representing the variable of ultrasound-visible yolk sac, when the variable of ultrasound-visible yolk sac is 0, the corresponding score on the scoring scale is 44; when the variable of ultrasound-visible yolk sac is 1, the corresponding score on the scoring scale is 0.

[0071] The evaluation scale combination consists of a total score scale and a surgical bleeding risk scale. The variable value is matched to the corresponding point on the variable line segment, and then the point is used as a vertical line of the variable line segment to correspond to the scoring scale above to obtain the score of the variable; the scores of the five variables are summed to obtain the total score; the total score value is matched to the corresponding point on the total score scale, and then the point is used as a vertical line of the total score scale to correspond to the surgical bleeding risk scale below to obtain the probability value of the patient's surgical bleeding risk. Medical staff evaluate the preparations that need to be made before surgery based on the probability value of the patient's surgical bleeding risk, such as: the configuration of medical staff, blood transfusion preparation, and the preparation of hemostatic drugs and equipment.

[0072] For example, the preoperative condition of a patient and the score according to the nomogram are as follows: the number of cesarean sections is ≥ 2 times, that is, the variable value of the number of cesarean sections is 2 (score 67.5); there is a history of uterine incision pregnancy, that is, the variable value of the uterine incision pregnancy history is 1 (score 75); the variable value of the yolk sac visible on ultrasound is 0, that is, the yolk sac is visible on ultrasound (score 44 points); the distance between the gestational sac and the uterine incision scar is 0, that is, the distance between the gestational sac and the uterine incision scar is 0-1cm (score 30); the diameter of the gestational sac is 1cm (score 10). According to the nomogram, the total score of the patient is 226.5 points, and the probability of surgical bleeding risk exceeds 0.9 (90%), indicating that the patient has a greater risk of artificial abortion bleeding and needs to take certain measures before surgery.

[0073] According to the nomogram, a history of more than two cesarean sections is scored 67.5 points, a history of pregnancy with previous uterine incision is scored 75.0 points, a visible yolk sac on ultrasound is scored 44 points, and a gestational sac within 2 cm of the scar is scored 30.0 points. The larger the maximum diameter (cm) of the gestational sac, the higher the risk score. After adding up the scores of each item, the higher the total score, the higher the risk of intraoperative massive bleeding; the corresponding score corresponds to the risk prediction value of intraoperative massive bleeding. For details of the nomogram, see Figure 1 .

[0074] 2.4. Evaluation of the nomogram prediction model

[0075] The validity of the nomogram prediction model was evaluated and the results showed that 2 =7.12, p=0.413. The discrimination of the nomogram model was evaluated by the conventional receiver operating curve (ROC curve) in the prior art. Among them, discrimination refers to the ability of the prediction model to correctly distinguish between individuals with a high probability of outcome events and individuals with a low probability of outcome events. The area under the ROC curve (AUC) is often used for evaluation. It is generally believed that AUC <0.60 indicates poor discrimination, 0.60-0.75 indicates that the discrimination has a certain value, and >0.75 indicates that the discrimination is better. The results showed that the area under the curve was 0.889, and the sensitivity and specificity were 91.50% and 70.50%, respectively. The verification results show that the model has good discrimination. For details of the results, see Figure 2 , Figure 3 .

[0076] In the inventor's previous research (Wen Yu, Analysis of high-risk factors for massive bleeding during artificial abortion of unplanned pregnancy after cesarean section, Journal of Chongqing Medical University, Vol. 48, No. 11, 2023), the study found high-risk factors for massive bleeding during artificial abortion of unplanned pregnancy after cesarean section, including: number of cesarean sections, maximum diameter of gestational sac, distance of gestational sac from uterine incision scar, embryonic arrest and pregnancy time. However, models such as nomograms have not been established based on the above factors, and it is still difficult to effectively predict the risk of bleeding. In actual operation, in response to different clinical situations, medical staff need to adopt certain hemostatic measures according to the risks to avoid adverse outcomes. The practical value of the results of the inventor's previous research is limited. It is necessary to discover risk factors that are more suitable for further application and establish corresponding prediction models and systems to provide effective references for preoperative preparation of medical staff.

[0077] In this technical solution, the cases were divided into a control group and a case group according to the amount of bleeding of 200 mL. The study found that the factors affecting bleeding include: the maximum diameter of the gestational sac, the number of cesarean sections, the history of uterine incision pregnancy, the distance between the gestational sac and the uterine incision scar, and the ultrasound-visible yolk sac. Compared with the prior art, the parameters added in this solution are: the history of uterine incision pregnancy and the ultrasound-visible yolk sac, and the factors reduced are: embryonic arrest and pregnancy time. Among them, the relationship between the ultrasound-visible yolk sac factor and the heavy bleeding in artificial abortion surgery is reported for the first time in this solution. As one of the key factors for assessing the risk of bleeding, it was not anticipated by the inventor before the experimental study. Moreover, from the perspective of the nomogram model established in this solution, the weight of the ultrasound-visible yolk sac factor is also relatively high (the score given by the ultrasound-visible yolk sac is 44 points), which is a very critical factor. If the variable of the ultrasonographically visible yolk sac factor is discarded in the nomogram model of this scheme, the independent risk factors shown in Table 2 (the other four independent risk factors except the yolk sac factor variable) are introduced into the R software according to the above method, and the RMS package is used to construct a nomogram model for predicting the occurrence of massive bleeding during artificial abortion. The discrimination evaluation result of the formed nomogram model will be greatly reduced, and the area under the ROC curve (AUC) will be much lower than 0.889 of this scheme, and will be reduced to below 0.7, and the application effect is not ideal.

[0078] According to the newly discovered five factors, the nomogram model is established, which can be used as the core part of the prediction system for massive bleeding during cesarean section and artificial abortion of unexpected pregnancy, and then the probability value of surgical bleeding risk is evaluated, and a good evaluation effect is obtained (the area under the curve is 0.889). The probability value of surgical bleeding risk is compared with the set threshold. When the probability value of surgical bleeding risk is greater than the set threshold, the system of this scheme sends an alarm signal to the medical staff. The medical staff can allocate surgical resources according to the risk value and invest more manpower and material resources in patients with higher bleeding risks. For patients with high bleeding risks, more experienced medical staff (director level, deputy director level, etc.) can be prepared, more sufficient hemostatic drugs and equipment can be prepared, and the blood bank can be notified to prepare for blood transfusion when necessary. In actual operation, the surgical bleeding risk threshold can be set to 0.5, 0.8, etc. according to actual needs. For example, according to actual conditions, a risk value of 0.5 (50% chance of massive bleeding) is a high-risk situation recognized by clinicians, and the threshold of this prediction system can be set to 0.5. If the calculated risk value of the actual case is greater than 0.5 and the system issues an alarm, relevant preparations need to be made before the operation. For example, the operation should be staffed with a deputy director-level or director-level medical staff, hemostatic drugs and instruments should be prepared, and the blood bank should be notified to reserve plasma.

[0079] 3. Discussion

[0080] In recent years, the global cesarean section rate has continued to rise. With the substantial increase in the number of people who have undergone cesarean section, the incidence of massive bleeding during artificial abortion has also increased accordingly. Studies have found that cesarean section can cause vascular and nerve damage, and permanent scars will form on the uterine incision after surgery; the uterus will adhere to the surrounding tissues after surgery, resulting in changes in the anatomical structure of the uterus. When this group of people undergo artificial abortion, the risk of massive bleeding, uterine perforation, and even maternal death is significantly higher than that of other types of artificial abortions compared with ordinary abortions. Therefore, it is called high-risk abortion, which is one of the maternal mortality factors that cannot be ignored. Therefore, it is of great significance to strengthen the risk warning and standardized management of massive bleeding during artificial abortion in unexpected pregnancies after cesarean section, and to formulate personalized diagnosis and treatment strategies for high-risk patients in advance, in order to reduce the risk of doctors and patients and ensure medical safety.

[0081] In this study, a total of 68 patients experienced massive bleeding during artificial abortion, accounting for approximately 30.36%; statistical analysis results showed that the number of births, the number of cesarean sections, the history of pregnancy with uterine incision, the distance between the gestational sac and the scar, and embryonic arrest were high-risk factors for massive bleeding during artificial abortion for unexpected pregnancy after cesarean section, which was consistent with previous research reports; at the same time, this study also found that the maximum diameter of the gestational sac under ultrasound and the visible yolk sac were high-risk factors for massive bleeding during surgery, which has not been reported in the literature.

[0082] In further logistic regression analysis, the number of cesarean sections, history of pregnancy with uterine incision, maximum diameter of gestational sac, distance between gestational sac and scar, and visible yolk sac on ultrasound were independent risk factors (P < 0.05). The reason for this may be that the larger the gestational sac, the larger the chorionic implantation area, the deeper the chorionic implantation, the higher the thickness of the decidua, and the closer the relationship between the embryonic tissue and the uterine myometrium. During the operation, it is difficult to aspirate the embryonic sac and decidua tissue in the uterine cavity, the operation time is relatively increased, the blood sinus of the embryonic implantation tissue closes slowly, and the uterine cavity accumulates a lot of blood, which is not conducive to uterine contraction, resulting in heavy bleeding.

[0083] In this study, the intraoperative hemorrhage rate of patients with 2 or more cesarean sections was significantly higher than that of patients with 1 cesarean section. Cesarean section can cause damage to the basal layer of the endometrium in the lower segment of the uterus, and the glandular epithelial cells in the basal layer of the endometrium are necessary for repairing the functional layer of the endometrium. Cesarean section damages the myometrium of the uterine wall, causing its continuity to be interrupted, forming a fissure or sinus leading to the uterine cavity. The incision heals poorly after cesarean section and the blood supply at the incision is insufficient, resulting in incomplete scar repair and a wide fissure at the scar. Some scholars believe that as the number of cesarean sections increases, the incision scar widens and the area increases, and the probability of gestational sac implantation in the scar site increases accordingly; the uterine scar enlarges, the fibrous tissue proliferates, and the surrounding muscle fibers are thin, which affects the contraction of the uterus, and the risk of hemorrhage during the next pregnancy artificial abortion increases accordingly. Moreover, the incidence of pelvic adhesions increases with the increase in the number of pelvic and abdominal surgeries; the normal anatomical position of the uterus changes after pelvic adhesions, and the probability of uterine perforation and hemorrhage during artificial abortion will also increase. Therefore, standardized and homogenized prenatal and postnatal care, advocacy of natural childbirth, strict control of the indications for the first cesarean section, and improvement of the cesarean section uterine incision suturing skills can effectively reduce the incidence of scar pregnancy and reduce the occurrence of heavy bleeding from artificial abortion after unplanned intrauterine pregnancy in this population.

[0084] This study found that the closer the gestational sac is to the uterine incision scar, the higher the risk of massive bleeding during abortion, which is consistent with previous studies. During abortion, if the gestational sac is too close to the uterine scar or located at the uterine scar, the negative pressure suction will cause scar tissue damage; after the gestational sac is sucked out, the scar area with sparse muscles will not contract effectively, resulting in increased bleeding. When the pregnancy tissue implants in the cesarean scar to form a cesarean scar pregnancy (CSP), the aforementioned operation is more risky and more likely to endanger the patient's life. In patients with CSP, the basal decidua at the uterine scar is often defective, and trophoblasts can directly invade the uterine scar and the surrounding myometrium and continue to grow, resulting in chorionic implantation at the scar; at this time, the vascular regeneration of the scar tissue myometrium is active, which is very likely to cause uncontrollable massive bleeding during abortion.

[0085] Standardized management of perinatal care for pregnant women, strict control of indications for first cesarean section; for women with scarred uterus who have no desire to have children in the short term, popularizing knowledge of efficient contraception during the perioperative period of cesarean section, promoting and effectively implementing PAC (post-abortion care) are very necessary primary prevention measures that can effectively reduce the massive bleeding during abortion in this group. For pregnant women with high-risk factors for massive bleeding from unplanned pregnancy and artificial abortion after cesarean section, such as advanced age, history of multiple abortions, multiple cesarean sections, embryonic arrest, and the gestational sac being too close to the uterine scar, full preoperative imaging evaluation and identification, implementation of preventive measures for massive bleeding during surgery, and establishment of a green treatment channel from outpatient department to inpatient department to operating room are indispensable secondary and tertiary prevention measures. The establishment and improvement of the above measures will help reduce the occurrence of massive bleeding from unplanned pregnancy and artificial abortion after cesarean section.

[0086] This study constructed a nomogram prediction model based on the results of multivariate logistic regression analysis. The results showed that clinical parameters such as ultrasound-visible yolk sac, maximum diameter of gestational sac, previous history of cesarean section, previous history of uterine incision pregnancy, and distance between gestational sac and scar can be scored accordingly. When used clinically, the prediction should be obtained from the top score of the nomogram model based on the risk factors involved in the patient, and the prediction probability should be evaluated with the total score, thereby providing a reference for early clinical intervention. This study also used a calibration curve (HL goodness-of-fit test) to evaluate the effectiveness of the model, and the result was χ 2 =7.12, p=0.413, indicating that the model is effective. The ROC curve was used to evaluate the discrimination of the model. The results showed that the area under the curve was 0.889, and the sensitivity and specificity were 91.50% and 70.50% respectively, indicating that the model has good discrimination.

[0087] In summary, the number of cesarean sections, the history of pregnancy with uterine incision, the maximum diameter of the gestational sac, the distance between the gestational sac and the scar, and the visible yolk sac on ultrasound are independent risk factors for massive bleeding during artificial abortion of unexpected pregnancy after cesarean section, which can provide a theoretical basis for early warning of the risk of massive bleeding in such abortion surgery during clinical diagnosis and treatment, and reduce medical risks. Since this study was based on clinical data from a single center, the research cycle was short and the sample size was small, the research conclusions were inevitably flawed. Therefore, we hope to prospectively collect sufficient clinical data in more clinical centers, enrich and improve the experimental results, in order to provide more objective and scientific theoretical support for early warning of the risk of massive bleeding in artificial abortion surgery for unexpected pregnancy with scarred uterus.

[0088] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A system for predicting massive bleeding during artificial abortion of unexpected pregnancy after cesarean section, characterized in that: It includes a variable input module and a nomogram model prediction module; The variable input module is used to input a variable of the maximum diameter of the gestational sac, a variable of the number of cesarean sections, a variable of a history of pregnancy with uterine incision, a variable of the distance between the gestational sac and the uterine incision scar, and a variable of a yolk sac visible by ultrasound; The variable of maximum diameter of gestational sac is the measurement of the maximum diameter of gestational sac in cm; The variable of the number of cesarean sections was referred to as 1 or 2; 1 represented 1 cesarean section and 2 represented ≥ 2 cesarean sections; The variable of history of hysterotomy pregnancy was represented by 0 or 1, where 0 represented no previous hysterotomy pregnancy and 1 represented previous hysterotomy pregnancy; The variable of the distance between the gestational sac and the uterine incision scar is represented by 0, 1 or 2; 0 means that the distance between the gestational sac and the uterine incision scar is 0-1 cm, 1 means that the distance between the gestational sac and the uterine incision scar is greater than 1 and less than or equal to 2 cm, and 2 means that the distance between the gestational sac and the uterine incision scar is greater than 2 cm. The variable of ultrasound-visible yolk sac was represented by 0 or 1; 0 represented ultrasound-visible yolk sac, and 1 represented ultrasound-unvisible yolk sac; The nomogram model prediction module includes a scoring scale, a variable line segment combination and an evaluation scale combination; The variable line segment combination consists of five variable line segments established according to the variables of the maximum diameter of the gestational sac, the number of cesarean sections, the history of pregnancy with uterine incision, the distance between the gestational sac and the uterine incision scar, and the variable of the yolk sac visible on ultrasound. The variable line segments are marked with scales representing the variable values. The evaluation scale combination consists of a total score scale and a surgical blood loss risk scale; The value of the variable is mapped to the corresponding point on the variable line segment, and then the vertical line of the variable line segment with this point corresponds to the scoring scale above to obtain the score of the variable; the scores of the five variables are summed up to get the total score; the total score value is mapped to the corresponding point on the total score scale, and then the vertical line of the total score scale with this point corresponds to the surgical bleeding risk scale below to obtain the probability value of the patient's surgical bleeding risk.

2. The system for predicting massive bleeding during artificial abortion after unexpected pregnancy after cesarean section according to claim 1, characterized in that: In the variable segment representing the number of cesarean sections, when the number of cesarean sections variable takes a value of 1, the corresponding score on the scoring scale is 0; when the number of cesarean sections variable takes a value of 2, the corresponding score on the scoring scale is 67.

5.

3. The system for predicting massive bleeding during artificial abortion after unexpected pregnancy after cesarean section according to claim 1, characterized in that: In the variable segment representing the variable of hysterotomy pregnancy history, when the variable value of hysterotomy pregnancy history is 0, the corresponding score on the scoring scale is 0; when the variable value of hysterotomy pregnancy history is 1, the corresponding score on the scoring scale is 75.

4. The system for predicting massive bleeding during artificial abortion after unexpected pregnancy after cesarean section according to claim 1, characterized in that: In the variable segment representing the variable of the distance from the gestational sac to the uterine incision scar, when the variable value of the distance from the gestational sac to the uterine incision scar is 0, the corresponding score on the scoring scale is 30; when the variable value of the distance from the gestational sac to the uterine incision scar is 1, the corresponding score on the scoring scale is 11; when the variable value of the distance from the gestational sac to the uterine incision scar is 2, the corresponding score on the scoring scale is 0.

5. The system for predicting massive bleeding during artificial abortion after unexpected pregnancy after cesarean section according to claim 1, characterized in that: In the variable segment representing the variable of ultrasound-visible yolk sac, when the variable value of ultrasound-visible yolk sac is 0, the corresponding score on the scoring scale is 44; when the variable value of ultrasound-visible yolk sac is 1, the corresponding score on the scoring scale is 0.

6. The system for predicting massive bleeding during artificial abortion after unexpected pregnancy after cesarean section according to claim 1, characterized in that: In the variable line segment representing the maximum diameter variable of the gestational sac, when 0<the maximum diameter variable value of the gestational sac ≤9, 0<the score on the corresponding scoring scale ≤100.

7. The system for predicting massive bleeding during artificial abortion for unexpected pregnancy after cesarean section according to any one of claims 1 to 6, characterized in that: It also includes a judgment module, which is used to compare the probability value of the surgical bleeding risk with a set threshold value; when the probability value of the surgical bleeding risk is greater than the set threshold value, the system sends an alarm signal to medical personnel.

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