Prevalence and risk factors for prelabor rupture of the membranes (PROM) at or near term in an urban Swedish population

Aims: To determine the prevalence, recurrence rate and to identify risk factors for prelabor rupture of the membranes (PROM) after 34 completed weeks in an urban Swedish population. Methods: In a retrospective cohort study a sample of 2880 women aged 25-41 years, resident in the city of Goteborg, was randomly selected from the population register. According to information from the national Medical Birth Register (MBR), 1507 of these 2880 women had given birth 2736 times. 2270 of these deliveries had occurred in hospitals in the city of Goteborg and case records for 2242 of these deliveries were found. The case records were systematically analyzed for the occurrence of FROM and potential risk factors for FROM. 2208 of these deliveries occurred after 34 weeks of gestation. The further analyses were based on these 2208 deliveries. Results: The prevalence of FROM after 34 week of gestation in this urban Swedish population was 12.9% and about 20% of the women in the population had experienced FROM at least once. In the multiple stepwise regression analysis, risk factors for FROM were primiparity, premature contractions, FROM in a previous pregnancy and bleeding in the first trimester. Conclusions: FROM is a common complication at or near term. The risk factors for FROM found in this representative study are difficult to influence and thus provide no guidance about how pregnancies should be managed to reduce the occurrence of FROM in the future.