Correlation between Clinical, Placental Histology and Microbiological Findings in Spontaneous Preterm Births

To examine the occurrence of chorioamnionitis and abruption among women who had a spontaneous preterm birth (SPTB), the correlation between clinical and placental findings, and the impact of these complications on neonatal outcome after delivery.

This was a retrospective case-control study conducted between 2008 and 2012 at a single teaching hospital. The study group included all women who had an SPTB (23-36 weeks). Placentas were cultured and underwent histological examination.

A total of 478 women were included. The mean gestational age at delivery was 32.6 ± 3.1 weeks. Overall, 260 (54.4%) women had either clinical and/or histological abruption or chorioamnionitis. Clinical chorioamnionitis was diagnosed before birth in 14 (2.9%) women, while histological chorioamnionitis (HCA) in 84 (17.4%). Overall, 38 neonates had infection. Placental cultures were negative in 65.8% (25/38) of these neonates, and in 77.1% (27/38), HCA was ruled out. Logistic regression analysis revealed that neonatal morbidity and mortality were correlated with gestational age at delivery (p = 0.02), not with placental pathology (p = 0.08).

Half of the women with PTB had clinical or histological abruption, chorioamnionitis or both. A partial correlation was found between clinical and placental findings. The main determinant of neonatal outcome was gestational age at delivery and not placental findings.