Exposure to selective serotonin reuptake inhibitors (SSRIs) or venlafaxine in early pregnancy is associated with a small increase in the risk of birth defects but this does not appear to be due to a teratogenic effect of the drugs, a large multinational cohort study has found. The cohort consisted of 2.3 million liveborn singleton children from five Nordic countries (Denmark, Finland, Iceland, Norway and Sweden). Antidepressant exposure was defined as a redeemed prescription from 30 days before the last menstrual period until the end of the first trimester.