Predictive value of amniotic fluid gram stain in postcesarean endomyometritis

The objective of this prospective study was to determine the value of the amniotic fluid Gram stain in identifying patients at high risk for postcesarean endomyometritis. Intraoperative samples of amniotic fluid were obtained from 151 patients undergoing nonelective cesarean section. Gram stains were performed and analyzed for the presence of bacteria and white blood cells (WBCs). Endomyometritis occurred in 55/151 (36% of patients. Positive Gram stain, defined as the presence of any bacteria in any high power field, occurred in 29/55 (53% of patients with endomyometritis as compared to 4/96 (4.2% of patients without endomyometritis (P < 0.001). The amniotic fluid Gram stain showed a sensitivity of 53% specificity of 96% a negative predictive value of 78% and a positive predictive value of endomyometritis of 88% which was higher than other clinical determinants evaluated. A positive test can therefore be used in clinical management by starting antibiotic treatment at the time of cesarean delivery. This may shorten the hospital course of endomyometritis and decrease maternal morbidity.