The association of placental abnormalities with maternal and neonatal clinical findings: a retrospective cohort study.

Objectives: (1) To determine the nature and extent of placental pathologic findings; (2) to associate placental pathologic findings with clinical indicators of infection; (3) to evaluate placental pathology in the context of the guidelines outlined by the College of American Pathologists (CAP).

Methods: A retrospective cohort study, through review of maternal and neonatal charts and placental pathology, of 100 sequential pregnancies in which placentas were submitted to pathology. Data were examined using descriptive statistics, and proportional differences were compared using the chi-square test and Fisher's exact test.

Results: Overall, 75% of placentas submitted for pathology review had pathologic abnormalities. Fifty percent had findings consistent with inflammation, 38% had findings consistent with vascular abnormalities, and 18% had findings consistent with meconium. Fetal clinical indicators of infection were associated with placental findings of chorioamnionitis (p < or = 0.01), while maternal clinical indicators were not. Similarly, fetal clinical indicators were associated with placental findings of fetal inflammation (p < or = 0.025), whereas maternal indicators were not associated with placental findings of maternal inflammation. A diagnosis of chorioamnionitis in labour by the attending physician was associated with pathologic findings (p < or = 0.05). A CAP indication was found in 75% of the placentas. There was no difference in incidence of placental pathology between those placentas submitted with and without a CAP indication.

Conclusion: Placental findings of inflammation or infection were associated with fetal clinical indicators of infection, but not with maternal indicators. Placental pathology is very useful in identifying undiagnosed maternal infection or inflammation.