Major depressive disorder is highly prevalent, with one in five people experiencing an episode at some point in their life, and is almost twice as common in women than in men. Antidepressants are usually given as a first-line treatment, including during pregnancy, either to prevent the recurrence of depression, or as acute treatment in newly depressed patients. Antidepressant use during pregnancy is widespread and since antidepressants cross the placenta and the blood-brain barrier, concern exists about potential long-term effects of intrauterine antidepressant exposure in the unborn child.