FDA pulls unproven premature birth drug Makena from market.

The FDA has ordered the immediate withdrawal of Makena, a drug intended to prevent premature births, from the US market after data showed it doesn't help pregnant women. The medication was the only drug approved in the US to help reduce the risk of early births in women with a history of preterm deliveries. The injectable drug is a synthetic version of the hormone progesterone, which can cause side effects, including blood clots, depression and allergic reactions. The FDA expedited Makena's approval in 2011 based on a small study suggesting it reduced rates of premature birth in women who had previously had trouble bringing a pregnancy to term.