593: Is maternal magnesium sulfate administration prior to delivery an independent predictor of survival in neonates who weigh fewer than five hundred grams?

Abstract

To determine if magnesium sulfate is an independent predictor of survival in neonates whose birth weight is fewer than five hundred grams. This was a retrospective cohort study of live-born neonates from 2012 to 2015 at an academic tertiary referral center. The primary outcome was survival from 12 hours of life until discharge. Neonates who did not survive the first 12 hours were excluded so that the results would not be confounded by limited intervention. Severe intraventricular hemorrhage (IVH, grade III-IV) was a secondary outcome. Multivariable logistic regression analyses were performed, controlling for potential confounders. Thirty-four deliveries were included; thirty were exposed to magnesium sulfate. Birth weights ranged from 310g to 495g (median: 450g); gestational ages ranged from 22 to 29 weeks (median: 24 weeks). The rate of survival from 12 hours until discharge was 76% (26/34). Maternal magnesium sulfate administration was associated with improved survival (OR= 22.3; 95% CI 1.9-607; p=0.023) while controlling for gender; corticosteroids and surfactant administration were removed due to collinearity with the exposure. Magnesium sulfate did not appear to protect from severe IVH (OR= 0.20; 95% CI 0.01-2.4; p=0.21). Maternal magnesium appears to be an independent predictor of survival from 12 hours after birth until discharge among neonates who are born weighing less than 500g. This is the first study that has found a survival benefit in these periviable birth weights.