A new study of American women at high risk of premature labour showed that giving them an intravenous infusion of magnesium sulfate, commonly known as Epsom salts, just before delivery cut the rate of cerebral palsy in their babies by half.

The study was was presented today, Thursday 31st January, at the annual meeting of the Society for Maternal-Fetal Medicine (SMFM), which is taking place this week in Dallas.

Study co-author, Dr John Thorp, who is McAllister distinguished professor of obstetrics and gynecology at the University of North Carolina (UNC) at Chapel Hill, said:

“This is one of the most promising breakthroughs in the management of high-risk pregnancies in more than 30 years.”

Doctors and patients can start using the treatment straight away if they wish, said Thorp. It will not have to be approved by the Food and Drug Administration because it is already used to treat women in labour for other reasons:

“Virtually every delivery room in the United States is already stocked with magnesium sulfate solutions,” said Thorp.

He explained that this study, together with another earlier Australian one, confirms that:

“We have a cheap, widely available treatment already in hand that cuts in half the risk of babies being born with an extremely disabling disorder. That is a tremendously exciting development.”

For this study, which was conducted at 20 sites across the US, including University of North Carolina hospitals, the researchers examined the effect of magnesium sulfate on the rate of stillbirth or infant death, and the rate of moderate or severe cerebral palsy at or after the age of 2 years.

They enlisted 2,241 women diagnosed as being at high risk for going into premature labour between weeks 24 and 31 of their term. The women were randomized to receive either an intravenous infusion of magnesium sulfate solution, or a placebo that looked exactly the same.

The infusions were started just before delivery was thought to be starting, at a dose rate of 6 grams over 20 to 30 minutes. This was then followed by a maintenance infusion at a dose rate of 2 grams an hour.

If delivery did not take place within 12 hours, the infusion was stopped and started again later, when it looked like delivery was about to take place again.

The results showed that:

  • There was no significant difference in the risk of infant death between the magnesium sulfate and placebo group.
  • However, moderate or severe cerebral palsy occurred about half as often in the magnesium sulfate group (1.9 per cent) than in the placebo group (3.5 per cent).

An earlier study carried out in more than 3,000 women in Australia had very similar results, said the researchers, who concluded, that after looking at both studies:

“The use of magnesium sulfate to prevent cerebral palsy in the children of women at imminent risk of early preterm delivery should be strongly considered.”

The lead author of the study was Dr Dwight J Rouse of the University of Alabama at Birmingham, and the research was carried out for the Maternal-Fetal Medicine Units Network of the National Institute of Child Health and Human Development, which funded it.

Source: UNC News (University of North Carolina).

Written by: Catharine Paddock, PhD