Abstract
BACKGROUND: The incidence of vaginal delivery complications (VDCs) has been increasing globally in recent years, posing a significant threat to maternal and neonatal health. The obstetric comorbidity index (OB-CMI) is a widely recognized tool that quantifies the burden of maternal comorbidities and predicts severe maternal morbidity or mortality during delivery and puerperium. However, it remains unclear whether there is an association between OB-CMI and VDCs. OBJECTIVE: The purpose of this study was to investigate the prevalence and spectrum of VDCs, and to explore the association between OB-CMI and VDCs. METHODS: This population-based cross-sectional study used data from the Shaanxi Province inpatients sample spanning from 2019 to 2022. We extracted all vaginal delivery data. Subsequently, maternal age and 20 comorbid conditions were assessed and weighted. The outcomes were the occurrence of VDCs. Cases of OB-CMI and VDCs were identified using the 10th Revision of the International Classification of Diseases (ICD-10) codes. The associations between OB-CMI and VDCs were estimated using logistic regression models, with both crude and adjusted models (for age, level of medical institution, and route of admission). RESULTS: A total of 536,362 women undergoing vaginal delivery were included in the study. The overall prevalence of VDCs in Shaanxi province, China, from 2019 to 2022 was 11.86%. The top five complications of vaginal delivery were retained placenta and membranes without hemorrhage, other obstetric injuries, postpartum hemorrhage, other complications of labor and delivery not classifiable elsewhere, and perineal lacerations during childbirth, collectively accounting for 99.3% of vaginal delivery complications. For each one-point increase in OB-CMI, there was a 10% increase of VDC incidence after adjustment. Among the different categories of VDCs, OB-CMI was associated with other obstetric lacerations (P = 0.002), postpartum hemorrhage (P < 0.001), retained placenta and fetal Membranes (P < 0.001), but not with perineal laceration (P = 0.175). CONCLUSIONS: The OB-CMI is associated with increased risk of VDCs, indicating its potential to inform prenatal counseling and facilitate personalized delivery planning. Women with an OB-CMI score greater than 7 should be closely supervised during vaginal delivery, and vaginal delivery is not recommended for women with an OB-CMI score greater than 10. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12884-025-08413-2.