SSRIs (Selective Serotonin Reuptake Inhibitors), which are found in most antidepressants (including Celexa, Lexapro, Prozac, Sarafem, Symbyax, Luvox, Luvox CR, Paxil, Paxil CR, Pexeva, Zoloft, and Viibryd), were added to the FDA's MedWatch after they were found to increase the risk of PPHN (Persistent Pulmonary Hypertension of the newborn).

PPHN is a condition in which a newborn's circulatory system is unable to properly process oxygen after leaving the womb. This lack of oxygen can cause a range of serious complications, including: permanent organ damage, incomplete lung development, or death. Symptoms of PPHN (which are usually seen within 12 hours of the birth) include: rapid breathing or heart rate, respiratory distress, or cyanosis (where the skin takes on a blueish tint).

While PPHN is a rare complication (affecting approximately 1 out of 700 newborns), studies have shown that mothers taking an SSRI during pregnancy are more likely to give birth to a child with PPHN.

Since the first warning connecting SSRIs to PPHN, which came after one study confirming the association, there have been numerous "inconclusive" studies concerning the risks of SSRIs. While the FDA confirms that none of the data gathered thus far is conclusive, they have notified consumers and healthcare professionals of the possible risks and plan to amend SSRI labels to include the possible risk of PPHN.