Bipolar disorder, also known as manic-depressive illness, is a brain disorder that causes significant changes in a person's mood and energy. The onset of bipolar disorder usually occurs during young adulthood and persists for the rest of a person's life, making women who are of childbearing age at risk for this disorder. Although overall relapse rates for pre-existing mood disorders are typically higher in women who are pregnant or recently gave birth than in other women, very little is known about the impact of pregnancy and the postpartum period on someone with bipolar disorder. The course and treatment of maternal mental illness during pregnancy and the postpartum period remains the center of much debate, particularly with respect to the use of psychotropic medications during pregnancy and breastfeeding. Identifying predictors of bipolar disorder recurrence during pregnancy and the postpartum period may help to determine which women are at highest risk and to develop new treatment guidelines. However, more information is needed to both identify predictors and develop guidelines that will improve outcomes for pregnant women with bipolar disorder and their babies. This study will evaluate pregnant women who have bipolar disorder to gain a better understanding of risk factors for bipolar disorder relapse during pregnancy and the postpartum period.