Preterm babies are significantly less likely to develop cerebral palsy if their mothers are given magnesium sulfate before childbirth, according to new research that could spark a shift in care for women who go into early labor.

Researchers believe that magnesium sulfate, commonly referred to as Epsom salts, may offer some neurological protection and prevent damage that can occur when the brain lacks oxygen, according to the study just published in the New England Journal of Medicine.

Epsom salts are relatively safe and affordable, and are already often given to pregnant women who may be at risk of having seizures. The salts are also given to some women to delay the onset of labor, though medical research hasn't supported their use in this capacity.

The findings should be strong enough to prompt health-care professionals to adopt the practice of using Epsom salts to reduce cerebral-palsy risk as well, according to Dr. Dwight Rouse, the study's lead author and a professor of obstetrics and gynecology at the University of Alabama at Birmingham.

"We now can say with reasonable certainty that we have a safe intervention that will reduce the chances that babies born very early will suffer cerebral palsy," Rouse said. "It's a drug that has a very high safety margin. ... (And) it's not expensive."

"Cerebral palsy" describes a group of conditions that affect body movement and muscular coordination. The disorder, which is still not fully understood by doctors, is caused by damage to certain areas of the brain, most often during fetal development. Babies born prematurely are at an elevated risk of developing cerebral palsy, and the level of risk is proportional to how early the baby is born.

The researchers studied 2,241 mothers who were at high risk for preterm delivery between 24 and 31 weeks of gestation. Babies are considered to be premature if they are born before the completion of 37 weeks. The women were randomly assigned to receive either magnesium sulfate or a placebo.

Researchers found that the overall rate of diagnosis of mild, moderate or severe cerebral palsy was lower, at 4.2 percent, among women who received Epsom salts, compared with 7.3 percent among the group that received a placebo. The risk of developing moderate or severe cerebral palsy was 1.9 percent in the magnesium-sulfate group, compared with 3.5 percent in the placebo group.

Rouse said women shouldn't be afraid to ask their doctors for Epsom salts if they are at risk of giving birth prematurely.

"If they find themselves in the unfortunate situation of facing an early preterm birth, they (should) raise the issue," he said. "North American obstetricians use (magnesium sulfate) regularly and this would be an extension of that use rather than a new drug that practitioners aren't familiar with and has a lot of side effects."

The use of magnesium sulfate did not reduce the risk of death among preterm infants. In both groups, death of the infant was three to four times more common than the development of moderate or severe cerebral palsy.

Frank Allen, chairman and chief operating officer of the Cerebral Palsy Support Foundation of Canada, said this study may represent a major step forward in the understanding of the disorder, which has not received as much attention or research funding as other major health issues.