The effects of antenatal corticosteroids therapy on very preterm infants after chorioamnionitis.

PURPOSE: To evaluate the effectiveness of antenatal corticosteroids (AC) therapy on outcomes of very low birthweight infants with histologic chorioamnionitis. METHODS: We performed a retrospective analysis of 10,935 single infants born at a gestational age between 22 + 0 and 33 + 6 weeks and birth weight <1,500 g. Clinical data were obtained from the Neonatal Research Network that included the tertiary neonatal intensive care units throughout Japan between 2003 and 2008. RESULTS: Data of 7,896 infants were available for the period 2003-2008 and were included in the analysis. According to logistic regression analysis, AC were significantly associated with reduced mortality [odds ratio (OR) = 0.50; p < 0.001], lower incidence of respiratory distress syndrome (OR = 0.72; p < 0.001), neonatal seizure (OR = 0.65; p = 0.003) and intraventricular hemorrhage (OR = 0.68; p = 0.001) in cases after histologic chorioamnionitis compared with the cases had no AC therapy (n = 3,271 vs. 4,625). Antenatal corticosteroids were significantly associated with reduced mortality [odds ratio (OR) = 0.60; p < 0.001] among the cases without histologic chorioamnionitis. CONCLUSION: In the retrospective population-based study in Japan, AC exposure was significantly associated with a lower rate of death and neurological morbidity in cases with histologic chorioamnionitis. These outcome data in Japan will be important for further improvement of antenatal practice and care.