CESAREAN DELIVERY - MICROBIAL COLONIZATION IN AMNIOTIC-FLUID

OBJECTIVE: To determine the frequency, clinical significance and causa tive factors behind intraamniotic microbial colonization in uninfected parturients at the time of cesarean delivery. STUDY DESIGN: Amniotic fluid specimens for bacterial and mycoplasmal cultures were obtained b y direct aspiration at cesarean section from 251 pregnant women (24-43 completed weeks) who had no clinical infection at the time of the ope ration. The symptoms of maternal infection were followed postoperative ly for the first week of the puerperium. RESULTS: The prevalence of am niotic fluid microbial invasion was 29% (72/251). In patients not in l abor and with intact membranes, it was 13% (20/158); in patients in la bor and with intact membranes, 23% (5/22); and in those with ruptured membranes, 66% (47/71). The most common species isolated were Ureaplas ma urealyticum, Lactobacillus species and coagulase-negative;staphyloc occi. In the total 251 patients, clinically evident postoperative endo metritis was observed in 6 (2%) and wound infection in 10 (4%). In pat ients operated on and with intact membranes, no risk factors were foun d as regards amniotic fluid microbial colonization. In patients operat ed on after rupture of the membranes, the only significant risk factor as regards amniotic fluid microbial invasion was use of an internal m onitor before the operation (P < .0003) (relative risk 10.7, 95% confi dence limit 2.9-39.4). The relative risk of postoperative endometritis was 2.3 (95% confidence limit 1.3-4.3) in patients with microbial inv asion of the amniotic cavity as compared to patients without invasion. The corresponding risk value for postoperative wound infection was 1. 4 (95% confidence limit 0.6-3.1). CONCLUSION: Though the incidence of microbial invasion of the amniotic fluid before surgery was unexpected ly high, its clinical significance as regards maternal puerperal morbi dity appeared to be low. The use of internal monitoring during labor w as the only significant risk factor as regards amniotic fluid microbia l colonization in patients operated on after membrane rapture.