Impact of chorioamnionitis on short- and long-term outcomes in very low birth weight preterm infants: the Neonatal Research Network Japan.

Objective: To evaluate the short- and long-term outcomes among very low birth weight (VLBW) preterm infants after histologic chorioamnionitis (HCA).Methods: We performed a retrospective analysis of 5849 single infants (birth weight <1500g) born at a gestational age between 22+0 and 33+6 weeks. Clinical data were obtained from the Neonatal Research Network Japan between 2003 and 2007. Multivariable logistic regression analyses were performed to assess the effect of HCA on short- and long-term outcome.Results: According to logistic regression analysis, HCA was associated with lower incidence of respiratory distress syndrome (odds ratio [OR]=0.54; p<0.001), increased chronic lung disease (OR=1.68; p<0.001) and sepsis (OR=1.71; p<0.001) and as a short-term outcomes. There was no significant association with intraventricular hemorrhage (OR=1.11; p=0.33), periventricular leukomalacia (OR=1.07; p=.070) and death before discharge (OR=0.97; p=0.084). HCA was associated with increased home oxygen therapy (OR=3.09; p<0.001), but not with cerebral palsy (CP; OR=0.91; p=0.63), develop quotient<70 (OR=1.27; p=0.17), visual impairment (OR=1.08; p=0.77), severe hearing impairment (OR=1.28; p=0.62) and death (OR=0.98; p=0.91) before three years of age.Conclusions: In this retrospective population-based study in Japan, HCA was not a risk factor for death, neurodevelopmental impairment and CP in VLBW three-year-old preterm infants.