Specific Magnesium Sulfate Levels in Pregnant Women Are Associated with Lower Risk for CP, Study Suggests

A magnesium blood concentration between 3.7 and 4.4 mg/dL in women at delivery is associated with lower risks for preterm babies to develop cerebral palsy, according to a new study.

The study “Optimization of Maternal Magnesium Sulfate Administration for Fetal Neuroprotection: Application of a Prospectively Constructed Pharmacokinetic Model to the BEAM Cohort” was published in The Journal of Clinical Pharmacology.

While magnesium sulfate is indicated for neuroprotection of preterm babies (those who are born before 32 weeks of gestation), the optimal dosing schedule to prevent cerebral palsy is currently unknown.

The study authors investigated what is the optimal therapeutic magnesium exposure for pregnant women and its concentration in the blood that may prevent cerebral palsy in preterm fetuses.

They applied their previously established pharmacokinetic model of magnesium to a large cohort of pregnant women in the Beneficial Effects of Antenatal Magnesium Sulfate (BEAM) study. Pharmacokinetics is the study of how an organism affects a drug, in this case, magnesium.

Pregnant women in the BEAM study received magnesium sulfate to prevent cerebral palsy in their preterm offspring. The study was conducted in 20 different U.S. academic centers between December 1997 and May 2004. Authors used their model to determine the relationship between maternal serum magnesium level at the time of delivery and the development of cerebral palsy in the preterm babies.

From a total of 1,905 women included in their analysis, authors observed that while the incidence of cerebral palsy in the placebo control group (women who have not received magnesium) registered 6.4 percent, this number decrease to 3.6 percent in the magnesium-treated group. In numbers, this translated to 81 infants with cerebral palsy in the placebo group and only 23 infants in the magnesium sulfate group.

The pharmacokinetics model also identified that the blood concentration of magnesium at delivery that was associated with the lowest probability of delivering an infant with cerebral palsy was 4.1 mg/dL. Additionally, the simulated total dose of magnesium administered that was associated with the lowest probability of delivering an infant with cerebral palsy was 64 g.

Overall, “our population-based estimates of magnesium disposition suggest that to optimize fetal neuroprotection and prevent cerebral palsy, magnesium sulfate administration should target a maternal serum magnesium level between 3.7 and 4.4 mg/dL at delivery,” the team concluded.