Amniocentesis for Gram Stain and Culture in Preterm Premature Rupture of the Membranes

A retrospective study was conducted to assess the predictive value and clinical usefulness of amniotic fluid Gram stain and culture in the management of preterm premature rupture of the membranes (PROM). Amniocentesis was attempted in 79 patients and was successful in 53 patients for a success rate of 67%. The complication rate was 1.8%. Fiftythree patients from whom amniotic fluid was obtained after preterm PROM were studied. Patients were managed expectantly unless clinical chorioamnioitis developed, a positive Gram stain or culture was found, or a mature lung profile after 34 weeksʼ gestation was established. A low incidence of chorioamnionitis (5.5%), postpartum endomerritis (11%), and neonatal sepsis (3.5%) was found with expectant management. A statistically significant association between Gram stain and antepartum infection, postpartum infection, and neonatal infection was noted. Gram stain had a 100% sensitivity and 82% specificity as predictor of chorioamnionitis. Amniotic fluid culture had a 100% sensitivity and 76% specificity as predictor of chorioamnionitis. As predictor of a positive culture result, Gram stain had a sensitivity of 60% and specificity of 92%. No patient with a negative Gram stain or culture developed infectious sequelae regardless of the timing of amniocentesis. All positive Gram stains and cultures were found within 48 hours of rupture of membranes. Amniocentesis for Gram stain and culture has clinical usefulness in preterm PROM and, despite false-positive tests, the authorsʼ data support intervention on the basis of a positive Gram stain.