Is an Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) antidepressant medication, which is approved to treat depression, anxiety, panic, and other serious psychological disorders. These disorders can continue or intensify during pregnancy, which is why some expecting mothers use Effexor. Is critical during fetal development in the first trimester. Medications that disrupt this system could plausibly cause a heart defect or other birth defects. Persistent Pulmonary Hypertension of the Newborn (PPHN).