FDA pulls the only approved drug for preventing premature birth off the market

The U.S. Food and Drug Administration has pulled its approval for an unproven drug intended to prevent premature births. (Manuel Balce Ceneta/AP)

The Food and Drug Administration is pulling its approval for a controversial drug that was intended to prevent premature births, but that studies showed wasn't effective.

Following years of back-and-forth between the agency and the drugmaker Covis Pharma, the FDA's decision came suddenly Thursday. It means the medication, Makena, and its generics are no longer approved drug products and can no longer "lawfully be distributed in interstate commerce," according to an agency statement.