Factors influencing failed vaginal trial of labor and subsequent cesarean section in elderly multiparous women, and maternal and neonatal outcomes

Objective The rate of failed trial of vaginal delivery (TVD) requiring subsequent cesarean section (CS) is relatively high among elderly multiparous women, which seriously impacts maternal and neonatal health. This study aimed to systematically investigate the factors influencing such conversion to CS in this population and evaluate their effects on maternal and neonatal outcomes, thereby providing evidence for clinical interventions. Methods A retrospective analysis was conducted on all multiparous women aged over 35 years who had a history of vaginal delivery only, admitted to the First Affiliated Hospital of Jinan University from January 2022 to December 2023. After screening, the eligible subjects were divided into the vaginal delivery group and the converted cesarean section group. Univariate analysis was used to screen for potential influencing factors, followed by multivariate Logistic regression model to identify independent risk factors for conversion to CS. Meanwhile, differences in maternal and neonatal outcomes between the vaginal delivery group and the converted CS group were compared and analyzed. Results Among the 510 elderly multiparous women, 422 achieved successful vaginal delivery, while 88 underwent conversion to CS due to failed TVD. Univariate analysis showed that maternal age and gestational weight gain (GWG) in the converted CS group were significantly higher than those in the vaginal delivery group ( P < 0.05); there were statistically significant differences between the two groups in the incidence of gestational hypertension, hypothyroidism, and placenta previa ( P < 0.05). Multivariate Logistic regression analysis revealed that age [OR = 1.113, P = 0.021,95%confidence interval (CI): 1.016–1.218], GWG above Institute of Medicine (IOM) guideline (OR = 1.977, P = 0.044,95%CI 1.019–3.837), gestational hypertension (OR = 6.903, P = 0.000,95%CI 3.127–15.239), Premature rupture of membranes (PROM)(OR = 0.263, P = 0.003,95%CI 0.108–0.644), hypothyroidism (OR = .044, P = 0.004,95%CI 1.434–6.464), and placenta previa (OR = 8.097, P = 0.006,95%CI 1.800–36.415) were all independent risk factors for conversion to CS ( P < 0.05). The area under the receiver operating characteristic (ROC) curve of the binary Logistic regression model was 0.764 (95% CI: 0.709–0.820), indicating good predictive performance. In addition, the incidences of postpartum hemorrhage, neonatal asphyxia, fetal distress, and neonatal admission to the neonatal intensive care unit (NICU) in the converted CS group were significantly higher than those in the vaginal delivery group ( P < 0.05). Conclusion Conversion to CS due to failed TVD in elderly multiparous women is influenced by multiple factors, including maternal age, excessive GWG, and various pregnancy complications. In clinical practice, optimizing intrapartum management strategies, strengthening prenatal weight management, and enhancing fetal weight monitoring are expected to reduce the rate of conversion to CS and improve maternal and neonatal clinical outcomes.