The FDA is advising healthcare professionals against using magnesium sulfate injection for more than 5-7 days to stop pre-term labor in pregnant women.
Administration of magnesium sulfate injection to pregnant women longer than 5-7 days may lead to low calcium levels and bone problems in the developing baby or fetus, including the bones (osteopenia), and fractures. The shortest duration of treatment than can result in harm to the fetus is not known exactly.
This specific use of the drug is off-label, and is not an FDA-approved use of the drug. Magnesium sulfate is approved to prevent seizures in preeclampsia, a condition in which the pregnant woman develops high blood pressure and protein in the urine, and for control of seizures in eclampsia. Both preeclampsia and eclampsia are life-threatening complications that can occur during pregnancy. Preeclampsia can lead to eclampsia, seizures, stroke, multiple organ failure, and death of the woman and/or baby.
As a result of this new safety information about low calcium levels and bone problems in the developing baby, the following information is being added to the drug label for Magnesium Sulfate Injection, USP 50%:
- A new warning stating that continuous administration of magnesium sulfate injection beyond 5-7 days in pregnancy for the treatment of pre-term labor can cause low calcium levels and bone changes in the baby.
- A new Teratogenic Effects section conveying the potential harm to developing babies by changing the Pregnancy Category to D from A. Pregnancy Category D means there is positive evidence of human fetal risk, but the potential benefits from using the drug in pregnant women may be acceptable in certain situations despite its risks.
- A new Labor and Delivery section emphasizing that continuous administration of magnesium sulfate injection to treat pre-term labor is not approved and that the safety and efficacy of use for this indication are not established. When used in pregnant women for conditions other than its approved indication, magnesium sulfate injection should be administered only by trained obstetrical personnel in a hospital setting with appropriate obstetrical care facilities.
Pregnant women should discuss with their health care professional the possibility of going into labor before term and the risks and benefits of any treatments that may be used.