WASHINGTON ¡ª Pregnant women and those who plan to become pregnant should avoid taking the antidepressant Paxil if possible because of the risk of birth defects, a group of obstetricians said Thursday.

The opinion issued by the obstetric practice committee of the American College of Obstetricians and Gynecologists comes nearly a year after the Food and Drug Administration and manufacturer GlaxoSmithKline reclassified the drug to reflect studies in pregnant women that showed the drug poses a 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 at the time.

The American College of Obstetricians and Gynecologists also said the decision whether to treat pregnant women with SSRIs, a class of antidepressants that includes Prozac, Zoloft and Lexapro as well as Paxil, should be considered on an individual basis.

Exposure to SSRIs late in pregnancy has been associated with short-term complications in newborns, the doctors said.

However, reproductive-age women have the highest prevalence of major depressive disorders. The benefit to the mother of treatment with any of the drugs may outweigh the risk to the fetus.

The opinion appears in the December issue of the journal Obstetrics & Gynecology.