An analysis of antenatal tests to detect infection in preterm premature rupture of the membranes.

The purpose of this study was to critically review published studies regarding sensitivity, specificity, and positive and negative predictive values of antenatal tests to diagnose chorioamnionitis or fetal-neonatal sepsis in preterm premature rupture of the membranes. A Medline Data-Base computer program search from 1980 to 1988 identified 39 studies, 23 of which were accepted after independent review with preset criteria. An ideal test to predict chorioamnionitis or neonatal sepsis was not found. The low success rate for amniocentesis and the need for repeat taps preclude the acceptance of tests on the basis of amniotic fluid. Single, small studies, the precision of which has never been tested, show good indices for repeatedly increased serum levels of C-reactive protein (greater than 20 mg/L), a high level of C-reactive protein greater than 40 mg/L, or a day-to-day coefficient of variation for C-reactive protein of greater than 30% in the prediction of histologic or clinical chorioamnionitis. Ultrasonographic observation of fetal activity, if published study results are confirmed, may be of value to predict amniotic fluid bacterial colonization.