Factors that predispose to premature rupture of the fetal membranes.

Causes of premature rupture of the fetal membranes were explored in a study of 25,820 pregnancies. Fourteen risk factors were analyzed using multivariate analysis. The following maternal factors had a positive association with premature ruptures: advanced maternal age, non-white race, multiparity, instrumentation of the cervix prior to pregnancy, cigarette smoking, incompetent cervix, low pregnancy weight gain, and recent coitus.