The FDA is advising healthcare professionals against using Magnesium Sulfate Injection for longer than 5–7 days to stop preterm labor in women. Prolonged administration of magnesium sulfate injection to pregnant women may lead to low calcium levels and bone problems in the developing baby or fetus, including osteopenia and fractures.

Magnesium sulfate is indicated to prevent seizures in preeclampsia and for control of seizures in eclampsia. Its use to stop preterm labor in women is off-label and is not FDA-approved.

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The following safety information is being added to the drug label for Magnesium Sulfate Injection, USP 50%:

  • A new Warning stating that continuous administration beyond 5–7 days in pregnancy for the treatment of preterm 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. 
  • A new Labor and Delivery section emphasizing that continuous administration to treat preterm 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.

For more information visit the FDA website