Preterm premature rupture of membranes, chorioamnion inflammatory scores and neonatal respiratory outcome

Objective To evaluate whether histological chorioamnionitis (HCA), in the setting of preterm premature rupture of membranes (PPROM), affects infant respiratory outcome. Design A prospective histological study on 287 consecutive placentas was performed in preterm infants (< 32+6 weeks gestation), categorised into four groups: according to the presence or absence of HCA, in the setting or in absence of PPROM. Setting Neonatal intensive care unit, Department of Pediatrics, Padua University, Padua, Italy from January 2001 to December 2006. Results Among the 287 NICU admitted preterm infants, 68/287 (23.6%) presented with HCA, 16/68 (23.5%) with a coexisting fetal inflammatory response, and 74/287 (25.7%) with PPROM. HCA was associated with a greater frequency of vaginal delivery (P < 0.0001), lower gestational age (P < 0.0001) and lower birth weight (P < 0.01). HCA had no effect on fetal lung maturation, however, it was a significant risk factor for CLD (RR; 95% CI 2.08; 1.30-3.33). HCA and the fetal inflammatory response were also significant risk factors for PPROM (RR; 95% CI 2.07; 1.42-3.03 and 2.64; 1.71-4.09 respectively). Conversely, HCA in the setting of PPROM failed to reveal any RDS protection or subtype CLD risk. Multivariate analysis demonstrated significant independent effects of presence of maternal HCA (P = 0.04), gestational age (P < 0.0001) and interaction HCA-gestational age (P = 0.04) on CLD development, regardless of the presence of fetal HCA or fetal HCA-gestational age interaction, PPROM or PPROM-gestational age interaction. Conclusions Histological chorioamnionitis is a significant PPROM and CLD risk factor, but it fails to provide any protection from RDS. HCA in the setting of PPROM also failed to reveal any RDS protection or subtype CLD risk.