The drug most commonly used to delay preterm labor in pregnant women has more — and more serious — side effects than alternatives without being any more effective, Stanford University researchers reported Friday.
Although it is generally not possible to stop labor completely, physicians try to delay it for at least 48 hours to allow transfer of the mother to a specialized hospital.
The drug most commonly used is magnesium sulfate, but nifedipine and some others occasionally are used.
“There is no free lunch with any of these drugs,” said Dr. Deirdre Lyell of the Stanford University School of Medicine’s Lucille Packard Children’s Hospital, “but magnesium sulfate has some particularly unpleasant side effects, including vomiting, lethargy and blurry vision. The alternative nifedipine often leaves women feeling better.”
Lyell and her colleagues studied 192 women in preterm labor at Packard Children’s and Santa Clara Valley Medical Center.
The team reported in the journal Obstetrics & Gynecology that, while magnesium sulfate quieted contractions more effectively than nifedipine, there was no difference in the treatments’ ability to delay delivery or in the birth weight of the infants.
But two-thirds of the women who received magnesium sulfate experienced mild to severe side effects, including shortness of breath and fluid buildup in the lungs.
Only one-third of the women receiving nifedipine experi-
enced side effects
