To determine survival and neurodevelopmental outcomes at 18 months corrected age among very low birth weight infants ≤32 weeks gestation with histologic chorioamnionitis.

Observational, regionalized, single-center cohort study with prospective follow-up.

Of the 628 infants meeting the selection criteria, 303 (48%) were born to mothers with evidence of histologic chorioamnonitis. Neonates with histologic chorioamnonitis were of lower gestational age and birth weight. On univariate analysis, they were more likely to have hypotension, bronchopulmonary dysplasia, severe intraventricular hemorrhage, severe retinopathy of prematurity, early-onset sepsis, and death. Infants with histologic chorioamnonitis were more likely to have any neurodevelopmental impairment, specifically, mental delay with a lower mental developmental index. When adjusting for perinatal variables, histologic chorioamnonitis had a protective effect on mortality rates (adjusted OR = 0.44, 95% CI: 0.24-0.8; P = .01; n = 619), had a nonsignificant effect on neurodevelopmental impairment (adjusted odds ratio = 1.33, 95% CI: 0.82-2.17; P = .25; n = 496), and was associated with a 4-point lower mental developmental index at 18-months follow-up (adjusted difference −3.93, 95% CI: −7.52 to −0.33; P = .03; n = 496).

Although infants with histologic chorioamnonitis were at an increased risk for death and neurodevelopmental impairment, after multivariate analyses, histologic chorioamnonitis was not associated with adverse long-term outcomes. Results suggest fetal protection from treatment-responsive maternal infection and inflammation.