Bacterial colonization of amniotic fluid in patients with intact membranes during labor.

Amniotic fluid from gravidas with intact membranes was obtained for bacteriologic culture at the time of cesarean section. The incidence of positive cultures from patients not in labor was 8%. When the length of labor was eight hours or less (mean 6.1 hours) and the membranes were intact, the incidence of positive cultures was 37%; in patients whose length of labor was 12 hours or less (mean 9.7 hours) with intact membranes, 55% of cultures were positive. The incidence of endomyometritis in patients with bacterial growth from the amniotic fluid cultures in each group was 33%, 33%, and 45%, respectively.