17P will now be marketed under the brand name Makena and given in weekly injections to pregnant women between 16 and 20 weeks gestation, continuing until 37 weeks gestation.
The approval will make Makena widely available in specialty pharmacies, thereby improving access to the drug.
March of Dimes senior vice president and medical director Alan Fleischman said that this was the first time that there was an FDA-approved treatment to offer women who have prematurely delivered a baby.
"Women who already have had a premature baby should check with their health care provider to see if this treatment is appropriate for them. This treatment is not for everyone," Fleishman said.