The significance of C-reactive protein levels in women with premature rupture of membranes.

In a prospective study of 100 patients with preterm premature rupture of membranes, clinical chorioamnionitis was present in 18 and histologic chorioamnionitis was present in 63. Patients who were managed conservatively for premature rupture of membranes were monitored by C-reactive protein determination, white blood cell and differential counts, maternal temperature, and fetal heart tone. C-reactive protein was measured nephelometrically (Immuno-chemistry Analyzer II, Beckman). Elevated C-reactive protein levels correlated well with both the pathologic and the clinical diagnosis of chorioamnionitis. Elevated C-reactive protein levels (at least 12 to 24 hours before delivery) were more sensitive than other standard laboratory or clinical tests in predicting chorioamnionitis both by clinical and pathologic criteria. When C-reactive protein values were normal, clinical chorioamnionitis was rarely found, whereas pathologically diagnosed chorioamnionitis was found half of the time. We conclude that although the C-reactive protein level is a very sensitive predictor of infectious morbidity in premature rupture of membranes, its specificity is not high.