In the United States, magnesium sulfate has become the most commonly used drug for treating preterm labor. Magnesium sulfate is given only intravenously. A woman is given an initial infusion of 4 ...

By ABC13 Friday, June 21, 2013 HOUSTON Andrea Cox is getting an IV of a drug called magnesium sulfate. It's because of a condition called pre-eclampsia that caused her baby to be born a month early.

Administering the drug on an off-label basis for more than 5 to 7 days to stop preterm labor presents the risk of osteopenia and bone fractures in exposed infants.