Context Prenatal magnesium sulfate may reduce the risk of cerebral palsy or
death in very preterm infants.
Objective To determine the effectiveness of magnesium sulfate given for neuroprotection
to women at risk of preterm birth before 30 weeks' gestation in preventing
pediatric mortality and cerebral palsy.
Design, Setting, and Patients Randomized controlled trial at 16 tertiary hospitals in Australia and
New Zealand with stratification by center and multiple pregnancy. A total
of 1062 women with fetuses younger than 30 weeks' gestation for whom birth
was planned or expected within 24 hours were enrolled from February 1996 to
September 2000 with follow-up of surviving children at a corrected age of
2 years.
Interventions Women were randomly assigned to receive a loading infusion of 8 mL (4
g [16 mmol] of 0.5 g/mL of magnesium sulfate solution or isotonic sodium chloride
solution [0.9%]) for 20 minutes followed by a maintenance infusion of 2 mL/h
for up to 24 hours.
Main Outcome Measures Rates of total pediatric mortality, cerebral palsy, and the combined
outcome of death or cerebral palsy at a corrected age of 2 years.
Results Data were analyzed for 1047 (99%) 2-year survivors. Total pediatric
mortality (13.8% vs 17.1%; relative risk [RR], 0.83; 95% confidence interval
[CI], 0.64-1.09), cerebral palsy in survivors (6.8% vs 8.2%; RR, 0.83; 95%
CI, 0.54-1.27), and combined death or cerebral palsy (19.8% vs 24.0%; RR,
0.83; 95% CI, 0.66-1.03) were less frequent for infants exposed to magnesium
sulfate, but none of the differences were statistically significant. Substantial
gross motor dysfunction (3.4% vs 6.6%; RR, 0.51; 95% CI, 0.29-0.91) and combined
death or substantial gross motor dysfunction (17.0% vs 22.7%; RR, 0.75; 95%
CI, 0.59-0.96) were significantly reduced in the magnesium group.
Conclusions Magnesium sulfate given to women immediately before very preterm birth
may improve important pediatric outcomes. No serious harmful effects were
seen.