Objective: To study the clinical risk factors for preterm premature rupture of membranes (PROM).
Method: We conducted a case-control study of 138 patients with PROM between 24 and 35 weeks' gestation and 267 control subjects.
Results: In stepwise multiple logistic regression models, the population of cases was more likely to be of low social class. Other risk factors for PROM were smoking in pregnancy, 1st or 2nd-3rd trimester hemorrhages, cervical incompetence and a documented cervico-vaginal infection during index pregnancy. First trimester hemorrhage and a documented cervico-vaginal infection during index pregnancy were associated with preterm PROM both in nulliparous and in multiparous women.
Conclusion: Few potentially remediable risk factors are associated with the occurrence of preterm PROM.