Debate on administration of magnesium sulfate to pregnant women to prevent cerebral palsy in preterm infants

Cerebral palsy (CP) is the most prevalent chronic childhood motor disability with an estimated lifetime cost of nearly $1 million per individual. There is evidence that magnesium sulfate (MgSO4) can reduce the incidence of CP for very early preterm infants.

Many thousands of pregnant women and their fetuses are exposed to MgSO4 every year in the United States for a variety of indications, and most obstetricians are comfortable with its use. Yet, there is still some controversy over whether magnesium sulfate is truly protective against CP. In three articles published in the June 2009 issue of the American Journal of Obstetrics & Gynecology, the authors shed some light on the debate.

Investigators from the Perinatology Research Branch (Division of Intramural Research), Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the NIH, Bethesda, and Detroit, and the Center for Molecular Medicine and Genetics, Wayne State University, Detroit, conducted a systematic review and meta-analysis of six randomized controlled trials involving 4796 women and 5357 infants. Writing in the article, Dr. Roberto Romero and Dr. Agustin Conde-Agudelo concluded that “Antenatal magnesium sulfate should be considered for use in women at high risk of delivery before 34 weeks of gestation, mainly in those with premature rupture of membranes, labor in active phase, and planned delivery within 24 hours.” They found persuasive evidence that administration of magnesium sulfate significantly reduces the risk of cerebral palsy in children at risk.

Continuing the debate, in an article summarizing a roundtable discussion at the 29th Annual Meeting of the Society for Maternal–Fetal Medicine, San Diego, CA, January 30, 2009, two researchers from the Division of Maternal–Fetal Medicine, Department of Obstetrics and Gynecology, Washington University–St. Louis,, and the Division of Maternal–Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California–San Francisco, enumerate the pros and cons of magnesium sulfate use for CP prevention. In a spirited conversation, they each talk about the available trials and observational studies and the strengths and weaknesses of each.

Participating in the roundtable, Alison G. Cahill, MD, MSCI, and Aaron B. Caughey, MD, PhD, observe, “Despite well-designed and executed studies, the answer to the question of whether evidence-based medicine supports the use of magnesium for neuroprophylaxis in all preterm pregnancies remains unclear.”

Dwight J. Rouse, MD, of the Center for Women's Reproductive Health, University of Alabama at Birmingham, offers his clinical opinion on the use of MgSO4 to prevent cerebral palsy. He notes that “three large, randomized placebo-controlled trials of antenatal magnesium sulfate (MgSO4) for fetal neuroprotection have recently been conducted and reported. The results of these trials provide strong support for the utilization of MgSO4 to lower the risk of cerebral palsy among the survivors of early preterm birth. In the United States, the use of MgSO4 for fetal neuroprotection has the potential to prevent 1000 cases of handicapping cerebral palsy annually.”

The articles are:

“Antenatal Magnesium Sulfate for the Prevention of Cerebral Palsy in Preterm Infants

“Magnesium for Neuroprophylaxis: Fact or Fiction?” by Alison G. Cahill, MD, MSCI, and Aaron B. Caughey, MD, PhD

“Magnesium Sulfate for the Prevention of Cerebral Palsy” by Dwight J. Rouse, MD

These contributions appear in the American Journal of Obstetrics & Gynecology, Volume 200, Issue 6 (June 2009) published by Elsevier.