Aug. 28--Expectant mothers at high risk of giving birth prematurely can lessen their newborns' risk of cerebral palsy by taking magnesium sulfate, according to a study involving researchers at the University of Utah.

The study, published in today's issue of The New England Journal of Medicine, involved 2,241 pregnant women from across the country, including many from Utah. The majority of the women had preterm ruptured membranes before labor.

In the days before delivery, they were randomly given intravenous magnesium sulfate or a placebo.

Doctors sometimes use magnesium sulfate to stop premature labor, but the treatment is not all that effective, said Michael W. Varner, a professor and vice chair for research in Obstetrics and Gynecology at the University of Utah and one of the study's co-investigators.

But curiosity about its potential to curb cerebral palsy was raised by a study of California birth certificates. That research showed premature babies whose mothers were exposed to magnesium sulfate during birth had lower rates of the neurological disorder, Varner said.

In the new study, babies whose mothers had received the treatment:

--Showed lower rates of all forms of cerebral palsy, at 4.2 percent. Babies in the placebo group had a rate of 7.3 percent.

--Developed moderate to severe cerebral palsy at a rate of 1.9 percent. Children born to mothers who received the placebo had a rate of 3.5 percent.

The disorder, which affects a child's ability to control movement, is believed to stem from abnormal development during pregnancy, shortly after birth or in the first few years of childhood. Researchers are still unsure of its exact cause.

Christi Johnson, 27, of Spanish Fork agreed to participate in 2004, when she was told her son Tagger would be born prematurely. The boy, now a healthy 4-year-old, was born at 31 weeks and weighed about 3 pounds.

"I remember listening to all the risks and how scared I was," Johnson said. "That's when they came in and started talking to me about this study. If I can help just one baby by doing this study, it was more than worth it."

The rate of full-term babies who develop cerebral palsy is one in 1,000. But for premature babies, the rate is 20 to 50 in 1,000, Varner said.

"Cerebral palsy is a devastating lifelong problem," Varner said. "One in every 500 babies are born with it. In Utah terms, that's about two a week."

The study was co-funded by the National Institute of Neurological Disorders. Utah patients were recruited through a partnership between the University of Utah and Intermountain Healthcare.

cmayorga@sltrib.com

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