Babies who were exposed to Paxil in utero mostly had atrial and ventricular septal defects. These types of defects are holes in the heart chamber walls that can sometimes require the infant to undergo surgery. While these types of heart defects occur in about 1% of the regular population, these studies found that the risk was between 1.5% and 2% for women who took Paxil during their first trimester.

Persistant Pulmonary Hypertension of the Newborn

The results of a study that looked at the use of antidepressants during pregnancy in mothers of babies born with a serious condition called persistent pulmonary hypertension of the newborn (PPHN) were published in February, 2006 in The New England Journal of Medicine. The study found that babies born to mothers who took SSRIs (including Paxil) 20 weeks or after in their pregnancies were 6 times as likely to have persistent pulmonary hypertension than babies born to mothers who took no antidepressants while pregnant. PPHN is a potentially fatal condition of the lungs that can occur shortly after birth and cause high pressure in the baby’s lung blood vessels. This means that the newborn is not able to get enough oxygen into its bloodstream.

Paxil: Pregnancy Class D

Paxil has been lowered to a pregnancy class D from class C, which means that studies in pregnant women demonstrate a risk to the fetus.  Category A means that controlled studies in pregnant women failed to demonstrate a risk to the fetus.  Category B means that the drug is presumed safe based on animal studies, with no controlled studies in pregnant women, or animal studies have shown an adverse effect that was not confirmed in controlled studies in women in the first trimester and there is no evidence of a risk in later trimesters.  Category C means that studies in women and animals are not available  or  studies in animals have revealed adverse effects on the fetus and there are no controlled studies in women.  Category D means that there is positive evidence of human fetal risk, however in some cases, the potential risk may be justified if there are no other alternatives.  Category X means that the drug is highly unsafe in pregnancy and that the risk of use outweighs any potential benefit.