Infants born very preterm have increased risks of death or neurosensory impairments and disabilities such as cerebral palsy, according to background information in the article. Although other studies have suggested that use of prenatal magnesium sulfate may act as a neuroprotective agent for very preterm infants, there have been no large randomized controlled trials in which magnesium sulfate was given solely for neuroprotection.
Caroline A. Crowther, M.D., of The University of Adelaide, South Australia, and colleagues conducted a study to determine the effectiveness of magnesium sulfate in preventing pediatric death and/or cerebral palsy when given to women at risk of delivery before 30 weeks' gestation.
The study was a randomized controlled trial at 16 hospitals in Australia and New Zealand. It included 1,062 women with fetuses younger than 30 weeks' gestation for whom delivery was planned or expected within 24 hours. The participants were enrolled from February 1996 to September 2000 with follow-up of surviving children at 2 years of age. Women were randomly assigned to receive an intravenous infusion of magnesium sulfate solution or sodium chloride solution (as placebo) for 20 minutes followed by a maintenance infusion for up to 24 hours.
Data were analyzed for 1,047 (99 percent) 2-year survivors. "Total pediatric mortality (13.8 percent vs. 17.1 percent; [17 percent reduced risk]), cerebral palsy in survivors (6.8 percent vs. 8.2 percent; [17 percent reduced risk]), and combined death or cerebral palsy (19.8 percent vs. 24.0 percent; [17 percent reduced risk]) were less frequent for infants exposed to magnesium sulfate, but none of the differences were statistically significant. Substantial gross motor dysfunction (3.4 percent vs. 6.6 percent; [49 percent reduced risk]) and combined death or substantial gross motor dysfunction (17.0 percent vs. 22.7 percent; [25 percent reduced risk]) were significantly reduced in the magnesium group," the researchers write.
"The potential clinically important improvement in pediatric outcomes from magnesium sulfate given to women immediately before very preterm birth for neuroprotection urgently needs confirmation in further trials. Widespread use of prenatal magnesium sulfate as a neuroprotective agent cannot be recommended solely on the basis of the current study. Although minor adverse effects are common in women receiving magnesium sulfate, there do not appear to be any serious harmful effects for the women or their children," the authors write. (JAMA. 2003;290:2669-2676. Available post-embargo at JAMA.com)
Editor's Note: This research was funded by a 5-year epidemiological project grant from The National Health and Medical Research Council Australia, The Channel 7 Research Foundation of South Australia Inc., and The Queen Victoria Hospital Research Foundation, Adelaide, South Australia, and supported by the Department of Obstetrics and Gynaecology at the University of Adelaide, South Australia.