New York City ? Doctors can cut the risk of cerebral palsy in half for very premature babies by giving their mothers magnesium sulfate just before they give birth, new research shows.

The mineral compound, also known as Epsom salts, is already used to treat pregnancy-related high blood pressure and to stop early labor. Doctors should consider giving it to women about to deliver an extremely preterm infant, said one of the researchers, Dr. John Thorp of the University of North Carolina.

“It’s cheap. It’s readily available. It doesn’t harm anybody. I think it will be widely adopted,” Thorp said.

The research was led by Dr. Dwight Rouse at the University of Alabama at Birmingham and was presented Thursday at a meeting of the Society for Maternal-Fetal Medicine in Dallas.

Cerebral palsy is a serious complication of premature birth. It’s caused by damage to the part of the brain that controls movement and results in poor muscle control and coordination.