Antenatal Magnesium and Cerebral Palsy in Preterm Infants

Objective To evaluate the relationship of maternal antenatal magnesium sulfate (MgSO₄) with neonatal cranial ultrasound abnormalities and cerebral palsy (CP). Study design In a randomized trial of MgSO₄ or placebo in women at high risk of preterm delivery, up to 3 cranial ultrasounds were obtained in the neonatal period. Images were reviewed by at least 2 pediatric radiologists masked to treatment and other clinical conditions. Diagnoses were predefined for intraventricular hemorrhage, periventricular leukomalacia, intracerebral echolucency or echodensity, and ventriculomegaly. CP was diagnosed at 2 years of age by standardized neurologic examination. Results Intraventricular hemorrhage, periventricular leukomalacia, intracerebral echolucency or echodensity, and ventriculomegaly were all strongly associated with an increased risk of CP. MgSO₄ administration did not affect the risk of cranial ultrasound abnormality observed at 35 weeks postmenstrual age or later. However, for the 82% of infants born at <32 weeks gestation, MgSO₄ was associated with a reduction in risk of echolucency or echodensity. The reduction in risk for echolucency explained 21% of the effect of MgSO₄ on CP (P = .04), and for echodensity explained 20% of the effect (P = .02). Conclusions MgSO₄ given prior to preterm delivery was associated with decreased risk of developing echodensities and echolucencies at <32 weeks gestation. However, this effect can only partially explain the effect of MgSO₄ on CP at 2 years of age. Trial Registration ClinicalTrials.gov: NCT00014989.