Biophysical profile in predicting acute ascending infection in preterm rupture of membranes before 32 weeks

To assess the performance of the biophysical profile (BPP) and its components within 24 hours of delivery in predicting histopathologic evidence of severe acute placental inflammation in women with premature rupture of membranes (PROM) before 32 weeks' gestation.

We examined placentas from a series of consecutive, nonanomalous, live-born, singleton infants delivered before 32 weeks' gestation after PROM. In 166 cases, biophysical profiles (BPP) were done within 24 hours of birth. Histologic evidence of acute inflammation was assessed in the maternal (amnion) and fetal (chorionic and umbilical cord vessels) compartments, and scored on a severity scale of 0-4 by a single pathologist masked to clinical data. The presence and severity of acute inflammation was related to BPP results and its individual components.

The overall prevalence of severe acute inflammation, ie, a score of 3 or 4, was 59% (98 of 166). In 30 (18%) cases it was present in the amnion, in 49 (30%) cases in chorionic or umbilical cord vessels, and in 19 (11%) cases in maternal and fetal compartments. There was no association between abnormal BPP score and presence or absence of severe acute placental inflammation (48% versus 46%, P =.7). Our study had a 90% power to detect a 0.26 difference between them. When rates of abnormal BPP scores were compared in cases with different degrees of acute inflammation in the maternal, fetal, or both compartments, no association was found. When the individual components of the BPP were analyzed in relation to site and severity of acute inflammation, no association was detected.

We did not find evidence of a dose-response relationship between acute placental inflammation and BPP score or its individual components in cases of PROM with infants delivered before 32 weeks. Mediators other than infection might affect BPP in preterm PROM.