Clinical analysis of the delivery outcomes of women with abnormal uterus

Jin-Fang Hu,Yan-Fang He*,Jun Xin

1North China University of Science and Technology Affiliated Hospital,Tangshan 063000,China.

Abstract Objective:To guide the pregnancy and delivery of patients with abnormal uterus through analyzing the delivery outcomes of them.Methods:A total of 32 pregnant cases with abnormal uterus were collected in the North China University of Science and Technology Affiliated Hospital from 2011 to 2018.7615 cases with normal uterus who visited the hospital and delivered during the same period were also collected.The rate of abnormal fetal position,premature rupture of membranes,premature delivery,postpartum complications,and caesarean section,were compared between the two groups by the χ2 test through SPSS.P values less than 0.05 were considered statistically significant.Results:There were significant differences in abnormal fetal position,premature rupture of membranes,premature delivery and spontaneous birth rate between the two groups(P＜0.05),but there was no significant difference in the incidence of postpartum hemorrhage between the two groups(P＞0.05).In the cause of cesarean section,there was significant difference in abnormal fetal position and scarred uterus(P＜0.05),but no significant difference in placenta previa and other causes(P＞0.05).Conclusion:Abnormal fetal position,premature rupture of membranes and premature delivery are more likely to occur in pregnant women with abnormal uterus than in normal ones.The rate of cesarean section in patients with abnormal uterus is significantly higher than that of normal uterus,due to the main reason of abnormal fetal position.Abnormal uterus is a high-risk factor for pregnant women,and patients with abnormal uterus should be strengthened the management of pregnancy and relaxed the indications of cesarean section.

Keywords:Abnormal uterus,Hypoplasia of uterus,Pregnancy outcome,High-risk pregnancy.

Introduction

The abnormal development of uterus is due to the fact that the development of accessory mesonephric duct during the 10th week of embryonic period,especially the process of single cavity formation when the lower segment and the tail end the tail end cross the anterior part of the mesonephric duct downward and inward,is disturbed or even interrupted by many internal and external factors[1].Malformed uterus mainly includes unicornous uterus,bicornuate uterus,double uterus,septate uterus,arcuate uterus and uterine dysplasia or undeveloped(primordial uterus,immature uterus).The abnormal development of uterus is often accompanied by abnormal development of other genital and urinary systems.Malformed uterus not only affects the normal menstruation,but also affects the implantation of fertilized eggs,even to cause infertility,abortion and so on.Because of the abnormal structure of malformed uterus,clinicians should closely observe such pregnant women as high-risk patients.This study analyzed the pregnancy outcome of pregnant women with abnormal uterus,so as to guide the prenatal treatment,the management of pregnancy and the choice of delivery mode.

Materials and methods

General information

From 2011 to 2018,a total of 7647 pregnant women,who gave birth in theNorth China University of Science and Technology Affiliated Hospital,were included.Inclusion criteria:(1)the maternal is 20-38 years old,with single natural pregnancy;(2)all pregnant women were confirmed by gynecological examination and B-ultrasound;(3)all the patients included signed the relevant informed consent.Exclusion criteria:(1)pregnant women aged over 38 or under 20;(2)patients with tubal obstruction,history of pelvic inflammatory disease,polycystic ovary syndrome and other factors affecting pregnancy were excluded.The subjects included 32 patients with malformed uterus and 7615 normal pregnant women.Among the 32 pregnant women with abnormal uterus,there were 3 cases with bicornuate uterus(9.4%),1 case with unicornous uterus(3.1%),7 cases with double uterus(21.9%),1 case with rudimentary horn of uterus(3.1%),and 20 cases with mediastinal uterus(62.5%).There was no significant difference between the two groups in terms of the number of pregnancies and the complications during pregnancy(P＞0.05)(Table 1).

Diagnostic methods

The diagnosis of abnormal uterus and normal uterus mainly depends on prenatal examination and ultrasound,prenatal examination,past medical history,hysteroscopy,laparoscopic exploration,and cesarean section.Of the 32 cases with abnormal uterus,9 cases(28.13%)were found by physical examination before pregnancy,4 cases(12.5%)by postpartum examination,16 cases(50%)by caesarean section,2 cases(6.2%)by postpartum ultrasound,and 1 case(3.12%)by previous abortion history.The missed diagnosis rate of abnormal uterus was as high as 56.25%in this study.

Statistical methods

All statistical analyses were performed using SPSS 22.0 statistical software.Statistical analysis was performed usingχ2tests for the comparison between the two groups.Pvalues less than 0.05 were considered statistically significant.

Results

Influences of malformed uterus on fetal position

The rate of abnormal fetal position in normal uterus group(5.6%)was significantly lower than that in abnormal uterus group(31.2%).Statistical analysis showed that there was significant difference in the rate of abnormal fetal position between the two groups(P＜0.05),as shown in Table 2.

Perinatal complications of malformed uterus

Statistical analysis showed that there were significant differences in the premature rupture of membranes and premature delivery between the two groups(P＜0.05).There was no significant difference in the comparison of postpartum hemorrhage between the two groups(P＞0.05)(Table 3).

The influence of abnormal uterus on delivery mode

The rate of cesarean section(75.0%)and fetal aspiration-assisted delivery(3.3%)in abnormal uterus group were higher than that of normal uterus group.There was significant difference in the rate of spontaneous delivery between the two groups(P＜0.05),as shown in Table 4.

Comparisons of caesarean section causes between normal uterus group and malformed uterus group

We compared the indications of cesarean section between the two groups,and the results are shown in Table 5.There were significant differences in abnormal position and scarred uterus between the two groups(P＜0.05),and there were no significant differences in placenta previa and other influencing factors(P＞0.05).

Discussion

The uterus originates from the accessory mesonephric duct.The malformed uterus is one of the abnormal development during the process of embryonic development,due to the disturbance of bilateral accessory mesonephric duct by many internal and external factors,often accompanied with abnormal urinary system.Clinically,malformed uterus can be divided into unicornous uterus,bicornuate uterus,double uterus,septate uterus,arcuate uterus and uterine dysplasia or undeveloped(primordial uterus,immature uterus)and so on.The reported incidence of malformed uterus is also different.According to various research,Ao Weihong et al.reported that the incidence of malformed uterus is in the range of 1%-0.98%,and mediastinal uterus is the most common[2],20 cases of mediastinal uterus were included in our study,which are the most common type of uterine abnormality and accords with the previous reports.

Table 1 Comparison of baseline characteristics between the two groups

Table 2 Comparison of the influence of malformed uterus on fetal position(n,%)

Table 3 Perinatal complications of normal uterus group and abnormal uterus group(n,%)

Table 4 Comparison of delivery mode between normal uterus group and abnormal uterus group(n,%)

Table 5 Causes of cesarean section in normal uterus group and abnormal uterus group(n,%)

At present,it’s well known that pregnancy guidance is very important for reducing the adverse outcomes of malformed uterus.In this study,the rate of missed diagnosis of malformed uterus is as high as 56.25%.Clinically,prenatal examination of pregnant women should be strengthened and the detection rate of malformed uterus should be enhanced,in order to receive early detection,diagnosis and treatment.Once diagnosed,patients with malformed uterus should be included into the management of high-risk pregnant women in time.For the patients with abnormal uterus who are not pregnant and have reproductive requirements,clinicians can formulate a reasonable surgical plan according to the patient’s own conditions,and carry out corrective surgery for these patients,relieving the abnormal uterus state and improving its uterine function[3].Through the above methods,patients with abnormal uterus can gradually recover,and obtain a satisfactory pregnancy outcome.

Different surgical treatments can be adopted for different types of abnormal uterus.For unicornous uterus or bicornuate uterus which does not affect the pregnancy outcome,no special treatment is usually given clinically.If unicornous uterus is complicated with severe residual angle deformity,it is easy to cause dysmenorrhea and increase the risk of endometriosis[4].Therefore,the residual corners should be removed before pregnancy.Strassman’s orthopaedic surgery can be performed before pregnancy in patients with bicornuate uterus prone to recurrent abortion.Rechberger T[5]believe that Strassman's orthopaedic surgery before pregnancy can significantly reduce the incidence of uterine rupture during pregnancy and complications during childbirth,and effectively improve the survival rate of the fetus.For patients with septate uterus companied with recurrent abortion and infertility without obvious cause,hysteroscopic septal hysterectomy is the first choice in clinical treatment.Esmaeilzadeh S[6]and other scholars believe that hysteroscopic septal hysterectomy can effectively reduce the infertility rate and abortion rate,prolong the gestational weeks,and improve the full-term live birth rate and the quality of live newborns.Because double uterus and arcuate uterus have relatively little influence on the adverse outcome of pregnancy,special surgical treatment is generally not adopted in clinic.If there are other factors leading to infertility or abortion risk,assisted reproductive technology is mostly used in clinic.

For pregnant women with abnormal uterus,medical staff should manage them according to the high-risk pregnant women,and reduce their anxiety and fear[7].Patients should be informed to relax and reduce activities,in order to decrease the occurrence of abortion.In addition,patients should pay attention to nutrition supply during pregnancy and avoid having sex.It is better to receive early fetal protection treatment and strengthen prenatal examination and management.At the same time,for pregnant women with threatened abortion symptoms,fetal protection drugs should be used rationally to reduce the re-damage to the uterus according to the different types of abnormal uterus.Clinically,for pregnant women with residual horn uterine pregnancy,once the diagnosis is clear,the residual horn and the ipsilateral fallopian tube should be removed immediately.Unilateral uterine pregnancy generally does not require special treatment,but should be vigilant about the occurrence of uterine torsion,strengthen monitoring and nursing during pregnancy.

In this study,we found that the abnormal rate of fetal position in abnormal uterus group was significantly higher than that in normal uterus group.This may be explained by the reason that the uterine cavity become smaller due to the limited myometrial wall extension after pregnancy,resulting to the limitation of fetal movement in the mother.As a result,the incidence of abnormal fetal position in late pregnancy is significantly increased,and breech position is most common in clinic.In addition,abnormal uterine morphology often accompanies abnormal endometrial development.Implantation of fertilized eggs on abnormal uterine wall or mediastinum can lead to poor blood supply of placenta and fetus,leading to premature delivery or abortion[8].In the aspect of perinatal complications,the incidence of premature rupture of membranes and premature delivery in the abnormal uterus group was significantly higher than that in the normal uterus group,indicating that the proportion of normal full-term pregnancy in pregnant women with abnormal uterus was significantly lower than that in the normal ones.However,there was no significant difference in postpartum hemorrhage between the two groups.

The rate of cesarean section in pregnant women with abnormal uterus was significantly higher than that in normal pregnant women,which indicates that the activity and development of fetus in abnormal uterine cavity are greatly affected,and could not meet the basic requirement of spontaneous delivery[9],resulting in dystocia,the increased proportion of cesarean section[10],and the more complications after birth[11].In the comparison of etiology of cesarean section,the proportion of cesarean section caused by scarred uterus in normal pregnant women group was significantly higher than that of malformed uterus group.While the comparison of cesarean section caused by abnormal placenta in normal pregnant women group was significantly better than that of malformed uterus group.However,there is no significant statistical difference between the two groups in the comparison of cesarean section caused by placenta previa and other factors.Among other factors,a considerable number of pregnant women refuse to give birth due to prenatal fear and choose painless delivery,increasing the rate of clinical cesarean section.Therefore,we should strengthen prenatal evaluation and education for patients to guide them to choose the most suitable delivery way.

Clinically,abnormal uterus is not the absolute indication for caesarean section.Clinicians should make a comprehensive evaluation according to the birth canal and strength of pregnant women,the position and size of fetus,to formulate a reasonable individualized delivery plan for the pregnant women with abnormal uterus.As a result,the rate of caesarean section and the incidence of complications after operation can be reduced in abnormal uterus.However,for patients with obvious fetal distress,abnormal fetal position,adverse pregnant history and fear of vaginal trial delivery,clinicians should relax surgical indications and choose cesarean section to terminate pregnancy.After delivery,on the one hand,the vital signs,urine volume and postoperative complications of puerperal women should be closely monitored;on the other hand,antibiotics and oxytocin should be rationally used to reduce the incidence of puerperal infection caused by decidual exfoliation and vaginal bleeding for a long time.

To sum up,malformed uterus pregnant women are more likely to have abnormal fetal position,premature delivery,premature rupture of membranes and other adverse pregnancy outcomes than normal pregnant women.Therefore,the key to prevent such adverse effects lies in early diagnosis and early treatment.For non-pregnant women,surgical treatment should be performed to correct malformed uterus,to improve the conditions of fertilized eggs implantation and fetal development[12],and improve full-term fetal live birth rate.For pregnant women,nursing and propaganda during pregnancy should be strengthened and reasonable delivery plan should be formulated according to the patients’own condition before delivery,so as to reduce the complications after delivery and the adverse effects on pregnant women and perinatal infants.

Abbreviations

None.

Acknowledgments

None.

Competing interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

Statement of ethics

All procedures performed in the study involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.Informed consent was obtained from all individual participants included in the study.