Evidence Calls for Halt to Common Therapy to Delay Premature Labor -- September 29, 2006

Research Triangle Park, NC — One of the most common treatments for stopping premature labor — the use of intravenous magnesium sulfate (Epsom salt) to inhibit uterine contractions — is not effective and may actually cause fetal and newborn deaths, two obstetricians at Family Health International (FHI) state in a commentary published in the October issue of Obstetrics & Gynecology.

"There is no evidence that magnesium sulfate tocolysis actually stops preterm or very preterm birth," says Dr. David Grimes, an obstetrician/gynecologist, co-author of the commentary, and vice president for biomedical affairs at Family Health International (FHI). "This use of magnesium sulfate to stop preterm labor is ineffective, and the practice should stop, especially considering its risks."

In 2003, 12 percent of all births in the United States occurred before 37 weeks gestation. Such preterm birth is a major cause of newborn death and illness. The goal of tocolysis is to stall preterm labor long enough so that corticosteroids can be administered to the fetus, which helps develop the lungs to improve the chances of survival after premature delivery.

Neither The American College of Obstetricians and Gynecologists nor the Royal College of Obstetricians and Gynaecologists in the United Kingdom endorses use of magnesium sulfate for this purpose. Nevertheless, in North America, magnesium sulfate tocolysis has become the first-line treatment for stalling premature labor.

In their commentary, Dr. Grimes and Dr. Kavita Nanda, an FHI obstetrician/gynecologist, cite a systematic review of the randomized controlled trials on magnesium sulfate tocolysis published in the Cochrane Library, an international resource that provides the highest quality scientific evidence to health care professionals. This review, involving more than 2,000 women in 23 trials, concluded that magnesium sulfate tocolysis is not only ineffective, but also harmful to infants.

Dr. Grimes and Dr. Nanda point out that some evidence suggests magnesium sulfate may be associated with 1,900 to 4,800 fetal and neonatal deaths a year in the United States. Potential complications from magnesium sulfate to pregnant women include respiratory arrest from accidental overdoses and pulmonary edema, another life-threatening condition.

Alternative therapies are preferable to magnesium sulfate, the authors write in their commentary. "We found that the strongest evidence supports the use of calcium channel blockers, usually nifedipine," says Dr. Nanda. "Scientific evidence shows that calcium channel blockers reduce the rate of giving birth prior to 34 weeks gestation. They have fewer maternal side effects than magnesium sulfate does, and they confer more benefits to the infant."

Family Health International is dedicated to improving lives, knowledge, and understanding worldwide through a highly diversified program of research, education, and services in family health and HIV/AIDS prevention, care, and treatment. Since its inception in 1971, FHI has formed partnerships with national governments and local communities in countries throughout the developing world to support lasting improvements in the health of individuals and the effectiveness of entire health systems. FHI has a staff of 1,600 and offices in 40 countries.

For more information, contact media@fhi.org