Development and validation of a risk prediction model for preterm premature rupture of membranes: a cross-sectional study at North Wollo Zone governmental hospitals, Northern Ethiopia

Objectives To develop and validate a risk prediction model for preterm premature rupture of membranes (PPROM) to enable early identification of at-risk women and support clinical decision-making in North Wollo Zone, Ethiopia. Design A hospital-based retrospective cross-sectional study. Setting Six public hospitals in the North Wollo Zone, Northern Ethiopia. Participants A total of 1098 pregnant women were included in the study using systematic random sampling. Primary outcome measures Occurrence of PPROM. Methods Data were collected between 20 November 2023 and 20 March 2024, using structured interviews and medical record reviews. A risk prediction model was developed using Least Absolute Shrinkage and Selection Operator and logistic regression. Model performance was assessed through area under the curve (AUC), calibration plots and the Hosmer-Lemeshow test. Internal validation was conducted via bootstrap resampling. A simplified risk score was created to categorise women into high-risk and low-risk groups, and its clinical utility was evaluated using decision curve analysis. Results Among the 1098 participants (100% response rate), the mean age was 21.54 years (IQR: 18–26), with 57.2% aged 20–34 years. The prevalence of PPROM was 10.75% (95% CI 9.01% to 12.77%). Seven significant predictors were identified: maternal age <20 years, urinary tract infection, anaemia, history of PROM, pregnancy-induced hypertension, short birth interval and polyhydramnios. The model demonstrated good discrimination (AUC=0.873; bias-corrected AUC=0.87). A simplified risk score (range 3–13) using a cut-off of ≥6.5 classified women into low-risk and high-risk groups, with PPROM incidence rates of 4.76% and 38.7%, respectively. Decision curve analysis showed good clinical utility, and a nomogram was developed for individualised risk assessment. Conclusions PPROM remains a significant obstetric complication in the study area. The validated risk prediction model showed moderate to good performance and can be used to support early screening and risk-based management in antenatal care (ANC). Integrating the tool into routine ANC services, along with health education and management of modifiable risk factors, may help reduce PPROM-related adverse outcomes. Further external validation is recommended.