Meconium: a marker for peripartum infection

To test the hypothesis that the presence of meconium-stained amniotic fluid (AF) is associated with maternal and neonatal infection, both before and after delivery.

Nine hundred thirty-six laboring women were analyzed for the presence of meconium in amniotic fluid and occurrence of peripartum infection. Meconium was assessed clinically as thin, moderate, or thick. Intra-amniotic infection and endometritis were diagnosed by standard definitions. All patients were tested for vaginal group B streptococcus, bacterial vaginosis, and other aerobic organisms.

Meconium-stained AF was present in 28% of the study participants (9% thin, 12% moderate, 7% thick). The presence of meconium was associated with increased intra-amniotic fluid (17% versus 9%, relative risk [RRI 1.98, 95% confidence interval [CI] 1.3, 3.1), endometritis (10% versus 5%, RR 2.38, 95% CI 1.3, 4.4), and total infection (25% versus 13%, RR 2.19, 95% CI 1.5, 3.2). Thick meconium had higher infection rates than clear AF (44% versus 13%, RR 5.18, 95% CI 2.9, 9.3). Meconium was associated independently with peripartum infection by multiple logistic regression (RR 1.28, 95% CI 1.1, 1.6).

Meconium-stained AF is associated with increased peripartum infection, independent of other risk factors for infection. Thick meconium, in particular, is associated with a marked increase in peripartum infectious morbidity.