Maternal magnesium sulfate and the development of neonatal periventricular leucomalacia and intraventricular hemorrhage.

OBJECTIVE: Neonatal periventricular leucomalacia and intraventricular hemorrhage are strong correlates of cerebral palsy. Our objective was to evaluate the effect of maternal magnesium sulfate exposure on the incidence and severity of periventricular leucomalacia and intraventricular hemorrhage in preterm neonates.
METHODS: Nine hundred eighteen consecutive inborn neonates with birth weights from 500 to 1750 g were divided primarily into two groups on the basis of maternal exposure to magnesium sulfate. The groups were divided secondarily into two clinical groups, a physician-initiated group, which consisted of neonates delivered for maternal or fetal indications, and a preterm delivery group, which included neonates delivered as a result of preterm labor or preterm premature rupture of membranes. These clinical groups were stratified further into magnesium sulfate-exposed and -unexposed subgroups. Neonatal neurosonograms were performed on days 3 and 7 of life and described as normal or abnormal. Abnormal sonograms included any periventricular leucomalacia or intraventricular hemorrhage. Severe lesions included periventricular leucomalacia, periventricular leucomalacia with intraventricular hemorrhage, or grades 3 or 4 intraventricular hemorrhage. The magnesium sulfate groups and the clinical groups with their magnesium sulfate strata were compared for the incidence and severity of abnormal sonograms. They also were compared for maternal and neonatal characteristics.
RESULTS: Maternal magnesium sulfate exposure was not associated with reduction in the incidence of abnormal sonograms when compared with the unexposed group (27% compared with 33%, P = .06). However, fewer severe lesions were observed in the exposed group (14% compared with 21%, P = .004). When clinical groups were examined, magnesium sulfate was not associated with a decrease in abnormal sonograms (adjusted odds ratio [OR] 1.09, 95% confidence interval [CI] 0.78, 1.52, P = .40) or severe lesions (adjusted OR 1.11, 95% CI 0.73, 1.68, P = .42). Logistic regression analyses of magnesium sulfate exposure within clinical groups controlling for the confounding effects of maternal and neonatal characteristics revealed no protective effect of magnesium sulfate exposure on the incidence of abnormal sonograms (adjusted OR 1.01, 95% CI 0.70, 1.44, P = .97) or severe lesions (adjusted OR 1.01, 95% CI 0.70, 1.74, P = .69). Within clinical groups, the preterm delivery group exhibited an increased risk for abnormal sonograms (adjusted OR 1.63, 95% CI 1.01, 2.67, P = .05) and severe lesions (adjusted OR 9.79, 95% CI 3.27, 29.29, P = .001) when compared with the physician-initiated delivery group, independent of maternal magnesium sulfate exposure.
CONCLUSION: Maternal magnesium sulfate exposure had no protective effect on the incidence or severity of periventricular leucomalacia and intraventricular hemorrhage in preterm neonates. The prevalence of these lesions was correlated better with the clinical group of origin and indication for its use.