Bipolar disorder is a prevalent condition among women of reproductive age. It has been associated with high morbidity, worsened obstetrical outcomes, and a significant risk of suicide. The management of this disorder during pregnancy and in the postpartum period involves balancing the risks associated with medication exposure versus the risks associated with untreated or undertreated maternal illness. Existing studies have shown an increased risk of mood episode relapses during pregnancy when mood-stabilizing medications are discontinued. Other studies have shown even higher risks for relapse during the postpartum period, especially in women who do not take prophylactic medications. Data on the risks associated with mood stabilizing medications have largely been obtained from population-based cohort studies which are prone to confounding factors and there has been a lack of consistency in the finding of risks between studies. In this chapter, we have summarized the available literature on treatment outcomes using pharmacotherapy for bipolar disorder during pregnancy and the postpartum period. We will also discuss studies of relapse rates during pregnancy and postpartum both with and without the use of prophylactic medications.