Mirtazapine in pregnancy and lactation - A systematic review

Depression is common in pregnancy and associated with increased risk of adverse effects for the neonate. Treatment and prevention options include antidepressant therapy. The aim of this paper was to review the literature on safety of mirtazapine during pregnancy and lactation. In 31 papers a total of 390 cases of neonates exposed to mirtazapine during pregnancy or lactation have been described. There might be an association between mirtazapine and spontaneous abortion, however, this might be attributable to underlying psychiatric disease. An increased risk of major neonatal malformations associated with mirtazapine in pregnancy has not been reported. Although one study showed a nearly significant increase in occurrence of respiratory problems and hypoglycaemia, no indication of causality could be given. No other significant adverse effects on neonates were reported. Limited available data, four papers on 11 exposed neonates, suggest that use of mirtazapine during breastfeeding is safe due to a low relative infant dose. High plasma levels might be associated with increased body weight and sleep. However, the reported data are too scarce to come to a clear assessment of the risk of mirtazapine in lactation. No information is available on the use of mirtazapine in pregnancy and Poor Neonatal Adaptation Syndrome (PNAS) or neurobehavioral development at an age over one year. In conclusion, mirtazapine seems to be safe in pregnancy, especially regarding incidence of congenital malformations. There are not enough data available to come to a conclusion on the safety of mirtazapine during lactation.