Objective: Uncertainty surrounds the risks of lithium use during pregnancy in women with bipolar disorder. The authors sought to provide a critical appraisal of the evidence related to the efficacy and safety of lithium treatment during the peripartum period, focusing on women with bipolar disorder and their offspring. Methods: The authors conducted a systematic review and random-effects meta-analysis assessing case-control, cohort, and interventional studies reporting on the safety (primary outcome, any congenital anomaly) or efficacy (primary outcome, mood relapse prevention) of lithium treatment during pregnancy and the postpartum period. The Newcastle-Ottawa Scale and the Cochrane risk of bias tools were used to assess the quality of available PubMed and Scopus records through October 2018.