This article summarizes the considerable progress that has been made in recent years in our understanding of the risks of pregnancy-associated mood and anxiety disorders, effective somatic and nonsomatic treatments for those disorders, and the risks and benefits of psychotropic medications during pregnancy and breast-feeding. Ten to 15% of women develop syndromal depressions within the first 2 to 3 months postpartum, making this the most common serious medical complication of the puerperium. Prior history of depressive disorders, lack of social support, and stressful life events all increase the risk of postpartum depression. Psychotic mood disorders (commonly called postpartum psychosis) occur after approximately 1 to 2 deliveries per 1000. To ensure safety, women who develop postpartum psychotic symptoms should be hospitalized. History of bipolar illness increases the risk of postpartum psychosis to as much as 25%. Prior episodes of postpartum psychosis further increase the risk to 50%-75%. The risk of first onset or exacerbation of panic disorder or obsessive-compulsive disorder appears to increase during pregnancy and the puerperium.