Tocolytic magnesium sulfate exposure and risk of cerebral palsy among children with birth weights less than 1,750 grams.

The authors examined the relation between intrapartum magnesium sulfate exposure and risk of cerebral palsy in a case-control study of low birth weight children designed to control for confounding by the clinical indications for magnesium in pregnancy. Case children (n = 97) included all singleton children with cerebral palsy who were born in 1985-1989 in Atlanta, Georgia with a birth weight less than 1,750 g and whose mothers had not had a hypertension-related disease during pregnancy. Control children (n = 110) were randomly selected from the infant survivors using identical selection criteria. Data on magnesium sulfate exposure, labor and delivery, and infant characteristics were abstracted from hospital records. The authors found no association between exposure to magnesium sulfate and cerebral palsy risk (odds ratio = 0.9; 95% confidence interval: 0.3, 2.6) either in all children or in subgroups with varying likelihoods for exposure to magnesium. However, the association did vary by birth weight, with a protective effect being seen in children born weighing less than 1,500 g and an elevated risk in children with birth weights of 1,500 g or more; all confidence intervals included 1.0 except for the combined <1,500 g group. Several ongoing randomized clinical trials of magnesium and cerebral palsy may shed more definitive light on this relation.