The FDA reviewed two studies which found that women who took Paxil in the first three months of pregnancy were 1-1/2 to two times more likely to give birth to a child with a heart defect than women who took other antidepressants or pregnant women overall.
In December 2005, The Food and Drug Administration (FDA) warned pregnant women and their doctors of an increased risk of heart defects in newborns when taking the antidepressant Paxil (which goes by the generic name paroxetine). The FDA reviewed two studies which found that women who took Paxil in the first three months of pregnancy were 1 1/2 to two times more likely to give birth to a child with a heart defect than women who took other antidepressants or pregnant women overall.
Along with the warning, the FDA placed the drug into its second-highest category for risk of birth defects, advising patients that "this drug should usually not be taken during pregnancy." In a later warning, the FDA said that Paxil "should generally not be initiated in women who are in their first trimester of pregnancy or in women who plan to become pregnant in the near future."

In the studies cited by the FDA, the risk of heart defects is about 1 percent overall and rose to 1.5 to 2 percent in infants born to women taking Paxil. As a consequence of these studies, GlaxoSmithKline and the FDA reclassified Paxil 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.
Researchers have been concerned about selective serotonin reuptake inhibitors (SSRIs)—Paxil is in this category—on fetuses for some time, but the FDA's announcement now indicates significant risk, particularly since a large number of pregnant women (estimated as high as 20 percent) suffer from depression and are readily prescribed antidepressants, including Paxil.
Paxil Study

A study from Sweden found that birth defects were twice as common among Paxil users as among women taking other antidepressants or none at all, and that most birth defects involve holes and malformations in the chambers of the heart. The defects often heal on their own, but more severe cases must be surgically repaired.
Since Paxil was approved in 1993, it has become one of the world's most popular antidepressants, taken by tens of millions of patients. According to GlaxoSmithKline, about 25 percent of Paxil users are women of childbearing age, between 18 and 45.