Variables influencing the integrity of lower uterine segment in post-cesarean pregnancy

Cesarean scar niche, fertility and uterine rupture during labor - A retrospective study

OBJECTIVES

To determine how does a uterine niche diagnosed prior to conception, affects future fertility and obstetrical outcomes, in a group of patients with secondary infertility undergoing fertility treatments.

STUDY DESIGN

A retrospective case-control study was performed, recruiting patients after cesarean delivery, before fertility treatment. Using stored ultrasound photos and video loops, we determined niche's sonographic parameters during the preconception period and retrieved the fertility and obstetrical outcomes thereafter.

RESULTS

104 patients met the inclusion criteria, and 86 were available for analysis. 56 (65%) had uterine niches larger than 2 mm in depth, and 30 (34%) had a uterine scar of 2 mm or less. Demographic characteristics were not different between groups. No statistically significant differences were observed regarding rates of implantation and clinical pregnancy between the groups. There were four cases of cesarean scar rupture during failed trial of labor (TOLAC), all of which were in the group with larger than 2 mm niche (33% of all TOLAC cases in the respected group).

CONCLUSIONS

While it appears that pre-conception presence of uterine niches larger than 2 mm in depth does not adversely affect future fertility, these niches might serve as a risk factor for future uterine rupture during TOLAC.

Repair of the myometrial scar defect at repeat caesarean section: a modified surgical technique

Background

To investigate whether the existing surgical technique for uterine closure at repeat lower segment Caesarean section (LSCS) can be modified to achieve adequate residual myometrial thickness (RMT) to ensure scar integrity and reduce complications in future pregnancy.

Methods

Women with a significant scar defect at repeat LSCS had the anterior uterine wall closed by a single experienced obstetrician with a technique focused on recognition, mobilisation and apposition of the retracted myometrial edges at the boundary of the defect. This was aimed at anatomical restoration of the lower segment. The RMT at the scar area was assessed by postnatal pelvic ultrasound scan at three months.

Results

Thirty women with a history of at least one previous CS, incidentally found to have a large defect at operation underwent the technique with prior consent. A postnatal scan showed a mean residual myometrial thickness of 8.4 mm (SD ±1.3 mm; range 5.6–11.0 mm). The average operating time was 91 mins and the average blood loss 728 ml. Two women who underwent the repair have gone on to have a further uneventful CS.

Conclusion

This modified technique resulted in scan evidence of an RMT indicative of uterine wall stability postnatally and offers the potential for reducing the risk of rupture and placenta accreta spectrum (PAS) in future pregnancy.

Uterine rupture during pregnancy: The URIDA (uterine rupture international data acquisition) study

OBJECTIVE

To describe the characteristics and peripartum outcomes of patients diagnosed with uterine rupture (UR) by an observational cohort retrospective study on 270 patients.

METHODS

Demographic information, surgical history, symptoms, and postoperative outcome of women and neonates after UR were collected in a large database. The statistical analysis searched for correlation between UR, previous uterine interventions, fibroids, and the successive perinatal outcomes in women with previous UR.

RESULTS

Uterine rupture was significantly associated with previous uterine surgery, occurring, on average, at 36 weeks of pregnancy in women also without previous uterine surgery. UR did not rise exponentially with an increasing number of uterine operations. Fibroids were related to UR. The earliest UR occurred at 159 days after hysteroscopic myomectomy, followed by laparoscopic myomectomy (251 days) and laparotomic myomectomy (253 days). Fertility preservation was feasible in several women. Gestational age and birth weight seemed not to be affected in the subsequent pregnancy.

CONCLUSION

Data analysis showed that previous laparoscopic and abdominal myomectomies were associated with UR in pregnancy, and hysteroscopic myomectomy was associated at earlier gestational ages. UR did not increase exponentially with an increasing number of previous scars. UR should not be considered a contraindication to future pregnancies.

The B-mode sonographic evaluation of the post-caesarean uterine wall and its methodology: A study protocol

AIM

The aim of this study is to utilize the niche measurement guidelines outlined by Jordans et al. in order to establish normal values and accurate description of caesarean section scars in a normal population. After defining the normal distribution, abnormal pregestational scar characteristics will be identified for predicting adverse pregnancy outcomes.

METHODS

This is a prospective observational multicenter clinical study where women with a history of only one caesarean section and yet open family planning are enrolled. The uterine length, cervical length, niche length, niche depth, niche width, residual myometrial thickness, endometrial thickness, scar to internal os distance, anterior myometrial thickness superior and inferior to the scar and the posterior myometrial thickness opposite the scar, superior and inferior to it are measured in a pregestational uterus. The lower uterine segment is measured over a length of 3 cm during subsequent pregnancy and followed up until delivery.

RESULTS

Data from 500 patients will yield normal distribution curves for all predefined measurements. Establishing a correlation between deviations from the normal measures and adverse events would be instrumental for counseling women regarding subsequent pregnancy and mode of delivery.

CONCLUSION

This study will demonstrate the changes of the post-caesarean scar from a non-pregnant uterus until delivery and can confirm the importance of the scar characteristics in predicting pregnancy outcome.

Ultrasonic assessment has high sensitivity for pregnant women with previous cesarean section occurring uterine dehiscence and rupture: A STARD-compliant article

To investigate the diagnostic performance of ultrasound (US) for pregnant women with previous caesarean section (CS) occurring lower uterine segment (LUS) dehiscence and rupture.107 pregnant women with previous CS and LUS thickness of 1.0 mm or less were recruited, the LUS and myometrium was measured, and US findings suggestive of uterine rupture were compared with findings at laparotomy. The included pregnant women were assigned into 2 groups, including 64 pregnant women had vaginal delivery at full-term and 43 pregnant women underwent repeat CS at preterm.US findings suggestive of uterine rupture and dehiscence occurred in 18 women and 89 women, respectively; ten of them developed uterine rupture, and the incidence of uterine rupture was 9.34% (10/107). The sensitivity, specificity, accuracy, positive, and negative predictive values of US for the evaluation of LUS dehiscence and rupture were 100.0%, 91.8%, 92.5%, 55.6%, and 100.0%, respectively. There was no severe maternal obstetric complication, 1 fetus died, and the other fetuses were born with a 5-minute Apgar score of 7 to 10.US has high sensitivity and specificity for pregnant women with previous CS occurring LUS dehiscence and rupture.

Evaluation of the uterine scar stiffness in women with previous Cesarean section by ultrasound elastography: A cohort study

PURPOSE

To evaluate by means of elastography if the quantitative assessment of the cesarean scar elasticity is feasible using as reference the surrounding intact myometrium and to investigate if the cesarean scar stiffness is influenced by the clinical characteristics of the previous cesarean delivery.

METHODS

Prospective study including women with a previous Cesarean Section (CS) ≥ 37 weeks' gestation performed 12-15 months before. By transvaginal ultrasound two regions of interest (ROI) were selected: uterine scar (Region 1) and surrounding myometrium (Region 2). Strain index (SI) for each ROI was calculated and the Strain Ratio (SR) was defined as Region 1 SI/Region 2 SI. The primary outcome was to compare SR among women who were grouped in accordance to presence of previous vaginal delivery, CS during labor, type of suture or pyrexia during post-partum. The secondary outcome of this study was to evaluate the correlation between SR and maternal, neonatal and labor characteristics.

RESULTS

68 women were included. The mean SR was 1.8 ± 0.7 thus indicating an increased stiffness of the uterine scar compared to the surrounding myometrium. No significant differences were found in terms of SR according to presence of previous VD, CS during labor, type of suture or pyrexia during post-partum period. Strain Ratio was not correlated to maternal characteristics nor to labor and neonatal outcome.

CONCLUSIONS

Evaluation of uterine scar stiffness is feasible by using elastography. The stiffness of the uterine scar is higher than that of the surrounding myometrium and is not correlated to maternal and labor characteristics.

Identifying possible risk factors for cesarean scar pregnancy based on a retrospective study of 291 cases

Aim

Cesarean scar pregnancy (CSP) is a rare but life‐threatening type of ectopic pregnancy. This study's aim is to investigate the clinical characteristics and possible risk factors for cesarean scar pregnancy.

Methods

A clinically randomized, unpaired and retrospective case–control study was implemented. A study group of 291 CSP patients and a control group of 317 full‐term pregnant women with a history of cesarean section (CS) were recruited in our hospital from May 2013 to October 2018. Their demographic characteristics and medical and obstetric history were collected.

Results

Only symptoms suggestive of an impending abortion, such as vaginal bleeding with or without abdominal pain, were identified as the clinical characteristics of CSP. Maternal age older than 35 years, gravidity higher than 3 (especially gravidity higher than 5), more than two induced abortions (especially more than five abortions), an interval of less than 5 years (especially less than 2 years) between the current pregnancy and the last CS, history of CS performed in a rural hospital, history of induced abortions after CS and retroposition of the uterus were possible independent risk factors for CSP.

Conclusion

CSP is a result of a combination of multiple factors associated with CS. There are no unique early clinical features of CSP. As a unique type of ectopic pregnancy, early diagnosis, early termination and early clearance should be the treatment principles. Further research is needed to evaluate the relationship between the cesarean scar defect and CSP in the future.

Effect of Primary Elective Cesarean Delivery on Placenta Accreta: A Case-Control Study

Background

Cesarean section (CS) is an independent risk factor for placenta accreta. Some researchers think that the timing of primary cesarean delivery is associated with placenta accreta in subsequent pregnancies. The aim of this study was to investigate the risk of placenta accreta following primary CS without labor, also called primary elective CS, in a pregnancy complicated with placenta previa.

Methods:

A retrospective, single-center, case-control study was conducted at Peking University Third Hospital. Relevant clinical data of singleton pregnancies between January 2010 and September 2017 were recorded. The case group included women with placenta accreta who had placenta previa and one previous CS. Control group included women with one previous CS that was complicated with placenta previa. Maternal age, body mass index, gestational age, fetal birth weight, gravity, parity, induced abortion, the rate of women received assisted reproductive technology, other uterine surgery, and primary elective CS were analyzed between the two groups.

Results:

The rate of primary elective CS (90.1% vs. 69.9%, P < 0.001) was higher, and maternal age was younger (32.7 ± 4.7 years vs. 34.6 ± 4.0 years, P < 0.001) in case group, compared with control group. Case group also had higher gravity and induced abortions compared with the control group (both P < 0.05). Primary CS without labor was associated with significantly increased risk of placenta accreta in a subsequent pregnancy complicated with placenta previa (odds ratio: 3.32; 95% confidential interval: 1.68-6.58).

Conclusion:

Women with a primary elective CS without labor have a higher chance of developing an accreta in a subsequent pregnancy that is complicated with placenta previa.

The role of resveratrol on full - Thickness uterine wound healing in rats

OBJECTIVE

Healing of the uterus after cesarean section and myomectomy operation is clinically important. In this study, we aimed to investigate the effects of resveratrol (3,5,4'-o-trihydroxystilbene) on the wound healing process of the uterus in rats treated with resveratrol following full thickness injury of the uterus.

MATERIALS AND METHODS

Twenty-one female wistar albino rats were divided randomly into three groups (1) control group with no intervention (2) injury group with uterine full thickness injury (3) resveratrol group with uterine full thickness injury and treated with resveratrol. Resveratrol was injected by oral gavage at the doses of 0.5 mg/kg/day for 30 days following uterine full thickness injury. Vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) distributions were assessed using the immunohistochemical methods in tissue and ELISA methods in the tissue homogenate. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities were evaluated with colorimetric method and malondialdehyde (MDA) levels also were measured using high performance liquid chromatography in the tissue homogenate. The effects of resveratrol on the uterine histology also were evaluated histologically with the light microscopy.

RESULTS

Histological evaluation and immunohistochemical evaluations showed that treatment with a resveratrol significantly increased the thickness of the uterine wall and VEGF expression and decreased expression PDGF during wound healing. Biochemically, GPx and SOD activities were increased significantly after treatment with resveratrol. Additionally, resveratrol administration decreased MDA levels.

CONCLUSION

These results showed that the antioxidant effects of resveratrol has been shown to have a positive influence on wound healing of the uterus.

A preliminary study of uterine scar tissue following cesarean section

AIM

To compare smooth muscle cells, type I collagen, and apoptosis of the lower uterine segment of women who had/without a prior cesarean delivery.

METHODS

Alpha smooth muscle actin (α-SMA), type I collagen, and nuclear apoptosis were compared between the groups from lower uterine segment. Twenty-eight controls and 82 with one prior cesarean delivery were included. The women with a prior cesarean section were classified by time since the surgery: ≤3 years, >3 and ≤5 years, >5 and ≤7 years, >7 and ≤9 years, and >9 years.

RESULTS

Smooth muscle volume density (VD) % was significantly lower in women who had cesarean sections in first three groups than in the controls (all, P<0.01). Type I collagen VD% was similar among all groups and the controls. The number of apoptotic nuclei in the lower uterine segment of the scarred group was greater up to 3 years after surgery and less than in the control at 7-9 years. The number of non-apoptotic nuclei in the scarred group was greater than controls up to 7 years after surgery.

CONCLUSION

The lower uterine segment scar becomes stable at 3 years after cesarean delivery, and by 9 years, the scar is mature.