WASHINGTON – The Food and Drug Administration is strengthening its warning that the antidepressant Paxil may be associated with birth defects when it is taken during the first trimester of pregnancy. The FDA and GlaxoSmithKline have reclassified the drug, which goes by the generic name paroxetine, as a “Category D” drug for pregnant women. The classification means that studies in pregnant women have shown that the drug poses a risk to the fetus. But the FDA said the benefits of the drug to the mother may outweigh the risk to the fetus. Two studies of pregnant women who were taking Paxil during their first trimester have shown that their babies have heart defects at a rate that is as much as twice the norm, the FDA said. In general, these types of defects range in severity from those that are minor and may resolve without treatment to those that cause serious symptoms and may need to be repaired surgically. Typically, 1 percent of babies develop a defect of this nature. GlaxoSmithKline spokeswoman Gaile Renegar said the company is notifying doctors about the new information. She said the company not concluded there exists a definite, causal link between the drug and the increased incidence of birth defects. The company has previously cited another survey of births that it said does not note a comparable increase. 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! AD Quality Auto 360p 720p 1080p Top articles1/5READ MOREBlues bury Kings early with four first-period goals The defects are most often holes in the walls of the chambers of the heart. Some were minor; others could require surgery. The agency announced the strengthened warning Thursday. It issued a previous warning in September and expanded it when information from an additional study came in. Further studies are under way. The FDA is advising doctors not to prescribe Paxil to women who are in their first three months of pregnancy or to women who are planning to become pregnant, unless there are no other options. Women who are taking Paxil should talk to their doctor before going off the drug, the FDA said. Most of the heart defects reported in these studies were atrial and ventricular septal defects, which are holes in the walls of the chambers of the heart.