# Determinants of Premature Rupture of Membranes: A Three-Year Retrospective Analysis of Age, Parity, Delivery Mode, and Seasonality

## TL;DR

This study finds that younger first-time mothers and those needing cesarean delivery are more likely to experience premature rupture of membranes, with no seasonal pattern observed.

## Contribution

The study identifies maternal age, parity, and delivery mode as significant determinants of PROM in a temperate climate, while ruling out seasonal influence.

## Key findings

- PROM incidence was highest in women aged 25-29 and lowest in those ≥35.
- Primiparas had significantly higher PROM rates than multiparas each year.
- PROM was more common in pregnancies requiring cesarean delivery than in vaginal births.

## Abstract

Background: Premature rupture of membranes (PROM) precedes 8‑10% of births and remains a leading cause of neonatal morbidity. Although infection, prior obstetric history, and cervical pathology are recognized contributors, data on the relative influence of maternal age, parity, mode of delivery, and seasonality are inconsistent across regions. Clarifying these determinants could enhance antenatal risk stratification and guide preventive counselling.

Methods: We retrospectively reviewed all singleton deliveries recorded in a tertiary care obstetric database from January 2018 through December 2020. Maternal age was grouped as <20, 20‑24, 25‑29, 30‑34, and ≥35 years; parity was dichotomized (primipara vs. multipart). The final mode of delivery (vaginal vs. cesarean) and calendar month of birth were extracted. Incidence of PROM was compared among age groups by the Kruskal-Wallis test, between parity and delivery‑mode strata by χ² tests, and across months by the Friedman test; Holm-Bonferroni corrections addressed multiple comparisons.

Results: Across the three‑year period, PROM complicated 13.7% of deliveries. Incidence varied significantly by age (H = 19.95; p = 0.00051), peaking in women aged 25‑29 and lowest in those ≥35. Primiparas showed markedly higher PROM rates than multiparas each year (2018: 29.8% vs. 3.9%; 2019: 22.9% vs. 7.3%; 2020: 23.3% vs. 6.2%; all p < 0.0001). PROM was likewise more frequent in pregnancies that ultimately required cesarean section (17.5‑20.2%) than in vaginal births (9.3‑11.1%) during each study year (all p < 0.0001). No significant month‑to‑month or seasonal trend was detected (χ² = 0.50; p = 0.779).

Conclusions: In this temperate‑climate cohort, PROM clustered in younger, first‑pregnancy mothers and was strongly associated with subsequent cesarean delivery, while advanced maternal age and seasonality exerted minimal influence. These findings highlight nulliparous women in the 20-29-year age group as a key population for targeted education, intensified surveillance, and early labor management planning. Future prospective studies should explore the biological mechanisms underlying the age‑parity interaction and evaluate interventions, such as infection screening or cervical support, that may mitigate PROM risk in this high‑incidence group.