Caesarean section in the first stage of labor and risk of cesarean uterine lacerations: a multicenter study in China

The surgical difficulty of cesarean delivery after a trial labor is often increased, leading to uterine lacerations, postpartum hemorrhage and other adverse outcomes. In the study, we aimed to identify and quantify risk factors that cause cesarean uterine lacerations during the first stage of labor. This was a retrospective cohort review of all women with a singleton, cephalic fetus at term delivered by caesarean section at four large departments in China between January 2023 and December 2024. A least absolute shrinkage and selection operator (LASSO) and multivariate analysis were performed to identify labor related risk factors for cesarean uterine lacerations among patients that underwent cesarean delivery in the first stage of labor. The risk factors were used to construct a new score model to identify patients at risk for cesarean uterine lacerations. During the study period, there were 11,689 women delivered by caesarean section, 206 women had cesarean uterine lacerations and 824 pregnant women without cesarean uterine lacerations were included in the study. The following 6 high-risk factors were identified for cesarean uterine lacerations by LASSO regression and multiple regression: occiput transverse position, occiput posterior position, cervical dilatation (> 5 cm), station of the fetal head at the ischial spines ( > + 1), caput succedaneum (> 3 cm), and duration of labor (> 12 h). In clinical variables model, the ROC curve analysis showed that the sensitivity and specificity to predict cesarean uterine lacerations were 91.372% and 92.205% respectively, with AUC 0.892. Using our new score model, when the score point ≥ 6, the sensitivity and specificity in identifying cases at high risk for cesarean uterine lacerations were 92.168% and 91.605%, respectively, with AUC 0.902. Increased risk of cesarean uterine lacerations in the first stage of labor is attributable mainly to fetal head position, larger cervical dilatation, lower fetal head, caput succedaneum, and duration of labor.