Women will be recruited through a tertiary level care program and advertisements in BC Children's & Women's Hospital as well as St.Paul's Hospital, Vancouver, B.C., Canada. If deemed eligible for the study (meeting a diagnosis of postpartum depression with or without comorbid anxiety disorder) and the potential participant agrees to participate, consent will be signed. The participant will return on a bi-weekly basis for study visits, where mood and anxiety will be monitored, in addition to blood pressure and weight. Starting dose of Desvenlafaxine is 50mg, and this can be titrated to 100mg/per day if needed. Questionnaires will assess depression symptoms, anxiety symptoms, quality of life, panic disorder, obsessive-compulsive disorder and generalized anxiety disorder.