Effect of degree of cervical dilatation at time of cesarean section on postpartum isthmocele formation

Aims: Isthmocele is a common long-term complication of cesarean delivery that causes various gynecological symptoms, primarily abnormal uterine bleeding.Although laborrelated factors are believed to contribute to the etiology of isthmocele, the relationship between cervical dilation and isthmocele development remains controversial.This study aims to evaluate the relationship between the degree of cervical dilation during primary cesarean section and the occurrence of postpartum isthmocele.Methods: This retrospective cohort study with prospective ultrasound assessment included women who underwent primary cesarean section between January 2023 and December 2024.Transvaginal ultrasonography performed 12 to 24 months postpartum assessed the presence of isthmocele and residual myometrial thickness.The primary endpoint was the presence of an isthmocele, defined as a notch at least 2 mm deep in the cesarean scar region.The relationship between the level of cervical dilation and isthmocele formation was evaluated using logistic regression analysis.Results: A total of 127 women (median age: 26 years, interquartile range 23-31) were included in the study.Of these, 84 had cervical dilatation less than 4 cm and 43 had cervical dilatation 4 cm or greater at the time of cesarean section.Isthmocele was detected in 24 (28.6%)women in the less than 4 cm group and 20 (46.5%) women in the 4 cm or greater group (p=0.070).In univariate logistic regression analysis, each 1 cm increase in cervical dilatation was associated with higher odds of isthmocele formation [odds ratio: 1.20, 95% confidence interval (CI): 1.05-1.38;p=0.007].However, this association was not significant after adjustment for potential confounders (adjusted odds ratio: 1.19, 95% CI: 0.97-1.45;p=0.087).Conclusions: A higher prevalence of isthmocele was observed among women with cervical dilatation of 4 cm or more at the time of primary cesarean section.However, cervical dilatation was not independently associated with isthmocele formation after adjustment for potential confounders.