February 1, 2008 (Dallas) — Intravenous magnesium sulfate supplementation before preterm delivery may cut the risk for cerebral palsy in half, according to new data presented here at the Society for Maternal-Fetal Medicine 28th Annual Meeting.
Magnesium sulfate is routinely given to prevent seizures in women with preeclampsia and to inhibit preterm labor. In addition, researchers reported here that the treatment may offer significant protection against moderate to severe cerebral palsy.
The multicenter study involved 2241 women, randomly assigned to receive either placebo (n = 1095) or a 6-g bolus of magnesium sulfate (n = 1041), followed by a further 2 g per hour for up to 12 hours. The vast majority of women — 87% — who entered the study had experienced a preterm membrane rupture. The women in the 2 groups had similar baseline characteristics, including gestational age at randomization, risk factor for preterm birth, and proportion of twins,
On follow up at age 2 years, babies born to women in the treatment group had a significantly lower rate of moderate to severe cerebral palsy, said Dwight Rouse, MD, from the University of Alabama at Birmingham School of Medicine. Specifically, 20 children, or 1.9%, had cerebral palsy in the treatment group, compared with 3.5% among the mothers who had received a placebo (relative risk, 0.55; 95% confidence interval, 0.32 – 0.95).
The analysis suggested that magnesium sulfate treatment of 63 women would spare 1 infant from cerebral palsy. The mechanism by which magnesium sulfate would prevent cerebral palsy is unclear, though the compound has been shown to reduce the risk for intravascular hemorrhage.
One small previous study had hinted that the supplement might increase the risk for fetal death. However, the results of the new randomized controlled trial presented here, involving women in danger of early delivery, but without preeclampsia, have not indicated such a risk.
The rate of fetal death was 9.5% in the treatment group and 8.5% among the women who had received a placebo — a difference that was not statistically significant. Moreover, when women with major congenital anomalies were excluded, the rates of death were almost equivocal.
"I think it's reassuring," Dr. Rouse told Medscape Ob/Gyn & Women's Health. As for what the results might mean for larger clinical practice, "the broader obstetrical community will have to come to a consensus." Other research has found similar results, including an Australian study published in the Journal of the American Medical Association in 2003.
More study of the issue would be logistically difficult, researchers said. The current trial took more than 6 years to conduct and involved more than 20 centers across the country. It was funded by the National Institutes of Health.
"There really isn't a drug to prevent cerebral palsy," said Roger Newman, MD, from the Medical University of South Carolina in Charleston, a session moderator who was not involved in the study. This study, "suggests an effective neuroprotective treatment."
The study was sponsored by the National Institutes of Health. Dr. Rouse and Dr. Newman have disclosed no relevant financial relationships.
Society for Maternal-Fetal Medicine 28th Annual Meeting: Abstract 1. Presented January 31, 2008.
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Cite this: Laura Beil. Magnesium Sulfate Reduces Risk for Cerebral Palsy - Medscape - Feb 01, 2008.