Antenatal scar thickness and intra operative findings in previous one cesarean section at team
- Kathmandu, Nepal ; Kathmandu University & Nepal Health Research Council (NHRC) ; 2025.
- 90p.
In partial fulfilment of the requirements for the degree of Master in Medical Research.
Introduction: The rate of CS is continuing to rise worldwide over time and its rate varies internationally from 10-25%. The frequency will further rise as women who undergo a cesarean delivery are much more likely to be delivered by a repeat operation in subsequent pregnancies. The option of vaginal birth after cesarean (VBAC) versus elective cesarean section (ERCS) is a critical decision influenced by factors such as maternal age, inter-pregnancy interval, scar integrity, and individual preferences (ACOG, 2020). Advantages of VBAC include avoidance of major abdominal procedure, decreased risk of postpartum hemorrhage, and puerperal infections and reduction in the recovery time after delivery. Uterine scar dehiscence is one of the complications associated with previous LSCS, in which there is disruption and separation of previous scar. The incidence reported for uterine scar dehiscence was between 0.2-4.3% of all pregnancies associated with previous cesarean section. Different modalities have been tried and tested to anticipate the risk for scar dehiscence and rupture. These includes use of obstetric risk assessment before trial of scar, antenatal assessment of scar thickness using ultrasound.
Objectives: The objective of this study was to correlate the antenatal sonographic lower uterine segment (LUS) scar thickness in women with previous one cesarean section at term with intra operative LUS scar grading.
Methodology: This was an Observational cross-sectional study done at Paropakar Maternity and Women’s Hospital (PMWH), Thapathali, Kathmandu from October 2023 to September 2024. This study included 80 patients with singleton, cephalic, at term pregnancy with previous one lower segment cesarean section admitted for elective repeat cesarean section, then the participants were counselled and informed consent was taken. Ultrasonography was done and antenatal scar thickness was measured which was correlated with intraoperative scar grading. Data analysis was done using SPSS software 29. Chi-square and p-value was derived taking cut off value of 2.5mm.
Results: In this study of 80 patients undergoing repeat elective cesarean sections, the prevalence was 13.87%, with 38.8% aged 25-29 years. Primipara patients made up 88.8%, and 43.8% delivered at 38 to 38 weeks and 6 days. The most common indication for primary cesarean was fetal distress (50%), followed by oligohydramnios (11.3%). An 83.8% inter-delivery interval greater than two years was observed. Intraoperatively, 6.25% had scar thickness <2.5 mm antenatally, 38.8% had flimsy adhesions, 10% had scar dehiscence, and. A cut-off value of 2.5 mm showed significant results (p = 0.021). With cut-off value at 2.5 mm, p value = 0.021, which is <0.05 and is significant and sensitivity, specificity, positive and negative predictive value was 25%, 95.8%, 40% and 92% respectively while with cut off value of 3.5mm it is 75%, 25%, 10% and 90% respectively.
Conclusion: Antenatally measured scar thickness by sonography correlated significantly with intraoperative scar grading. Ultrasonography evaluation of LUS can be used as a screening test to predict the lower uterine scar integrity. Risk of dehiscence is increased in women with thin LUS i.e. sonographic LUS thickness of <2.5 mm and needs to be further evaluated. Women with previous one LSCS with thick LUS i.e. sonographic LUS thickness of >2.5 mm, can be counselled regarding TOLAC if not contraindicated.
Keywords: Intraoperative scar grading, Previous cesarean section, Scar thickness measurement, Scar dehiscence, Trial of labor after caesarean.
Intraoperative scar grading. Previous cesarean section. Scar thickness measurement. Scar dehiscence. Trial of labor after caesarean.