The risk of infection for mother and baby after spontaneous rupture of the membranes was evaluated in a prospective study of 24 patients with ruptured membranes before the 36th week of pregnancy. The mean length of pregnancy after rupture was 10 days and 2 hours. Only patients harboring Group B streptococci or E. coli in the urogenital tract were treated with antibiotics (during delivery). With the exception of 1 woman, all patients harbored one or more pathogens in the urogenital tract. Four mothers were infected but all recovered. One of 26 infants died from infection. The study did not confirm any association between prolonged rupture of the membranes and the frequency of idiopathic respiratory distress syndrome, nor did it contradict attempts to actively prolong pregnancy after rupture of the membranes.