For many years, magnesium sulfate has been used to halt contractions when a pregnant woman goes into early labor. But, now, the U.S. Food and Drug Administration (FDA) is warning pregnant patients and health officials that the drug can pose a serious risk to the baby.
The agency is specifically urging doctors against using magnesium sulfate injections for more than 5 to 7 days to delay labor in pregnant women. Doing so can lead to low calcium levels and bone problems in the developing fetus, which include fractures and thin bones.
Magnesium sulfate is approved to prevent seizures in preeclampsia, a condition that develops when the woman has high blood pressure. However, this use of Magnesium sulfate is off-label.
Due to new safety warnings being issued, the following will be added to the drug label for Magnesium Sulfate Injection, USP 50%:
A warning that continuous use of this drug beyond 5 to 7 days, in pregnant women, can lead to low calcium levels and bone changes.
The drug warning category will switch from D to A. Category D means there is evidence to support risk to the fetus, but the potential benefits may outweigh the risks.
It will further state a new Labor and Delivery section that will emphasize continuous use to treat pre-term labor is not approved by the FDA.
Lastly, patients need to go over their options with their medical doctor and obstetrician to discuss the risk of early labor and the risks and benefits of available treatments should the situation arise.
Nearly a half million babies in the United States—that’s 1 out of every 9—is born premature each year, according to the CDC.