Do the Causes of Spontaneous Preterm Delivery Affect Placental Inflammatory Pathology and Neonatal Outcomes?

Objective: To investigate the severity of histologic chorioamnionitis /funisitis according to the indication for preterm delivery and their corresponding neonatal outcomes. Method: This study included 411 singleton women who delivered between 21⁺⁰ and 31⁺⁶ week of gestation due to preterm labor (PTL, n = 165), preterm premature rupture of membranes (PPROM, n = 202), or incompetent internal os of the cervix (IIOC, n = 44). The primary outcome measure was the rate of severe histological chorioamnionitis/funisitis. Secondary outcome measure was neonatal outcomes including neonatal and infant death, and neonatal composite morbidity. Results: The PPROM group demonstrated a higher rate of severe histological chorioamnionitis/funisitis compared to the PTL group (severe histological chorioamnionitis; PPROM, 66.3% vs. PTL, 49.1%, p = 0.001, severe funisitis; PPROM, 44.1% vs. PTL, 23.6%, p < 0.001) and this remained significant after multivariable analysis (severe histologic chorioamnionitis, OR 2.367, 95% CI 1.517–3.693; severe funisitis, OR 2.668, 95% CI 1.684–4.226). For neonatal outcomes only, a higher rate of patent ductus arteriosus was observed in the IIOC group compared to the PTL and PPROM groups (IIOC, 77.3% vs. PTL, 54.0% vs. PPROM, 54.0%, p = 0.043) and this remained significant after multivariable analysis. Conclusion: Indication of spontaneous preterm delivery might affect the placental inflammatory pathology and neonatal morbidity.