Abstract 1212 Poster Session II, Sunday, 5/2 (poster 82)

Retrospective studies suggest that the risk of cerebral palsy and intraventricular hemorrhage (IVH) may be reduced in the extremely preterm infant if they are exposed to magnesium in utero (Pediatrics 1995:95;263). The purpose of this study was to examine the effects of magnesium exposure on adverse outcome in ELBW infants born in the NICHD Neonatal Research Network between 7/96 and 6/98. Data were prospectively collected on maternal/infant conditions, magnesium exposure (including indications, timing and duration of magnesium). Of 1339 infants weighing 501-1000 grams, 744 (56%) were exposed to magnesium; 595 (44%) were not exposed. Multivariate analyses adjusting for birthweight, gestational age, race, gender, delivery mode, antenatal steroids, preeclampsia/eclampsia, and neonatal indocin were used to calculate the adjusted odds ratio (AOR) for effect of magnesium on mortality, IVH, ventriculomegaly (VM), and periventricular leukomalacia (PVL). Analyses were performed on infants weighing 501-750 g, 751-1000g and on the entire cohort (all infants 501-1000 g). (Table) No effect of magnesium exposure was observed for any birth weight group on mortality, all IVH or severe IVH. An increase in the incidence of PVL was evident only for the entire cohort. These results suggest that antenatal magnesium exposure is not associated with a reduction in severe IVH in ELBW infants, though PVL is increased. The long term effects of magnesium on neurodevelopmental outcome, particularly cerebral palsy, are uncertain and will be defined by the continued follow up of this cohort.

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