OBJECTIVES: To estimate the rate of admissions to NICUs, as well as infants' morbidity and neonatal interventions, after exposure to antidepressant drugs in utero. METHODS: Data on pregnancies, deliveries, prescription drug use, and health status of the newborn infants were obtained from the Swedish Medical Birth Register, the Prescribed Drug Register, and the Swedish Neonatal Quality Register. We included 741 040 singletons, born between July 1, 2006, and December 31, 2012. Of the infants, 17 736 (2.4%) had mothers who used selective serotonin reuptake inhibitors (SSRIs) during pregnancy. Infants exposed to an SSRI were compared with nonexposed infants, and infants exposed during late pregnancy were compared with those exposed during early pregnancy only. The results were analyzed with logistic regression analysis. RESULTS: After maternal use of an SSRI, 13.7% of the infants were admitted to the NICU compared with 8.2% in the population (adjusted odds ratio: 1.5 [95% confidence interval: 1.4-1.5]). The admission rate to the NICU after treatment during late pregnancy was 16.5% compared with 10.8% after treatment during early pregnancy only (adjusted odds ratio: 1.6 [95% confidence interval: 1.5-1.8]). Respiratory and central nervous system disorders and hypoglycemia were more common after maternal use of an SSRI. Infants exposed to SSRIs in late pregnancy compared with early pregnancy had a higher risk of persistent pulmonary hypertension (number needed to harm: 285). CONCLUSIONS: Maternal use of antidepressants during pregnancy was associated with increased neonatal morbidity and a higher rate of admissions to the NICU. The absolute risk for severe disease was low, however.