The perinatal period is a time of high risk for women with unipolar and bipolar mood disorders. We discuss treatment considerations for perinatal mood disorders, including unipolar and bipolar depression as well as postpartum psychosis. We further explore the unique issues faced by women and their families across the full trajectory of the perinatal period from preconception planning through pregnancy and following childbirth. Treatment of perinatal mood disorders requires a collaborative care approach between obstetrics practitioners and mental health providers, to ensure that a thoughtful risk : benefit analysis is conducted. It is vital to consider the risks of the underlying illness versus risks of medication exposure during pregnancy or lactation. When considering medication treatment, attention must be paid to prior medication trials that were most efficacious and best tolerated. Lastly, it is important to assess the impact of individual psychosocial stressors and lifestyle factors on treatment response.