Histologic chorioamnionitis is associated with fetal growth restriction in term and preterm infants

OBJECTIVE: Our aim was to evaluate associations between chorioamnionitis and fetal growth restriction in infants enrolled in the Collaborative Perinatal Project. STUDY DESIGN: A total of 2579 nonanomalous, singleton infants delivered at 28 to 44 weeks' gestation with chorioamnionitis were matched 1:3 for ethnicity, gestational age, parity, and maternal cigarette use (all of which were correlated with both chorioamnionitis and markers of fetal growth restriction) with 7732 control infants. Moderate or marked leukocytic infiltrates of the placenta defined chorioamnionitis. Birth weight, length, head circumference, weight/length ratio, ponderal index, and birth weight/head circumference ratio in the lowest 5th percentile were markers of fetal growth restriction. Placental weight and the birth weight/placental weight ratio were also evaluated. RESULTS: Compared with data on matched control infants, histologic chorioamnionitis was associated with all markers of fetal growth restriction and with low birth weight/placental weight ratios (odds ratios, 1.3-1.7). The strongest associations were found at 28 to 32 weeks' gestation (odds ratios, 2.2-11). Attributable risks for several markers of fetal growth restriction exceeded 50% in infants born at <33 weeks' gestation. CONCLUSION: Histologic chorioamnionitis is associated with multiple markers of fetal growth restriction, with stronger associations noted in prematurity.