Magnesium Sulfate Reduces Threat of Cerebral Palsy

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"If deemed to be at high or immediate risk of delivery prior to 32weeks, women and their doctors should consider using magnesiumsulfate to prevent their child from having cerebral palsy," saidstudy lead author Dr. Dwight J. Rouse, a professor of obstetricsand gynecology at the University of Alabama at Birmingham.
The findings are published in the Aug. 28 issue of theNew EnglandJournal of Medicine.
But in an editorial accompanying the study, other experts calledfor caution and more study before routinely recommending thetreatment to prevent cerebral palsy.
In the study, the largest of its kind, Rouse and his colleaguesrandomly assigned 2,241 women at risk of delivering early --between 24 and 31 weeks -- to receive either magnesium sulfate or aplacebo. (Babies born after 37 to 42 weeks of pregnancy areconsidered full term, according to the March of Dimes.) Themagnesium sulfate was given intravenously as the women enteredlabor as a 6-gram dose followed by a constant infusion of 2 gramsper hour until either 12 hours had passed, labor had subsided, orthey had given birth.
The researchers then compared infants born to each group of mothersto see if there were differences in the rates of death or theoccurrence of cerebral palsy.
Cerebral palsy, marked by abnormal movement control and posturesthat cause limited activity, is caused by damage or dysfunction tothe developing fetal or infant brain. Preterm birth is itself arisk factor for the condition. About one third of cerebral palsycases are associated with preterm birth.
In past studies, magnesium sulfate hasn't borne out as an effectivetreatment for delay of early labor. But it has proven effective fortreatment of maternal high blood pressure associated withpregnancy, Rouse said.
And some previous research had found magnesium sulfate effectivefor reducing the risk of cerebral palsy, but other studies had beeninconclusive. So, Rouse and his colleagues embarked on this large,more comprehensive study.
They found no significant differences in the proportion of deathsbetween the magnesium sulfate group and the placebo group. But theydid find that moderate or severe cerebral palsy was diagnosed injust 1.9 percent of the group treated with magnesium sulfate,compared to 3.5 percent in the placebo group.
Rouse said it's not known for certain how the compound may work.But, he said, it may "stabilize the vessels in the vulnerablepreterm brain," protect against damage from lack of oxygen, andguard against injury caused by swelling and inflammation.
"Our findings are applicable only to early preterm birth," headded. "We define high risk as threatening delivery prior to 32weeks."
Dr. William Zinser is a pediatric neurologist at Children's MedicalCenter, Dallas, and an associate professor of pediatric neurologyat the University of Texas Southwestern Medical Center. He said,"It's too early to know if magnesium sulfate has an overall effecton the incidence rate of cerebral palsy."
Zinser reviewed the study but was not involved with it. "Moreresearch needs to be done, certainly," he said.
Rouse said women at risk for preterm birth should discuss thepotential use of magnesium sulfate with their doctors.
More information
To learn more about preterm birth, visit the March of Dimes .
SOURCES: Dwight J. Rouse, M.D., professor of obstetrics andgynecology, University of Alabama at Birmingham; William Zinser,M.D., pediatric neurologist, Children's Medical Center, Dallas, andassociate professor of pediatric neurology, University of TexasSouthwestern Medical Center at Dallas; Aug. 28, 2008,New EnglandJournal of Medicine