(N Engl J Med. 2017;376(23):2245–2254)
Lithium is a first-line treatment for bipolar disorder in women of reproductive age in the United States, and has even been reported to reduce the risk of mood-episode recurrence during pregnancy and the postpartum period. However, infants born to mothers treated with lithium early in pregnancy are at increased risk for cardiac defects, although some small studies have shown conflicting results. Consequently, the authors of this large, retrospective cohort study evaluated the records of pregnant women nested in the US Medicaid Analytic eXtract (MAX), to provide evidence of the association between increased risk of neonatal cardiac malformations and maternal use of lithium in the first trimester.