Currently there are no controlled data on the management of postpartum depression that fails to respond to adequate antidepressant therapy. The investigators recently reported that a large number of patients responded to the addition of atypical neuroleptics after having failed antidepressant trials. Aripiprazole used adjunctively to antidepressants is effective in patients with resistant depression but it has not been studied in patients with resistant postpartum depression. The investigators propose to conduct a 6 week open-label study to assess the effectiveness and tolerability of aripiprazole used adjunctively to antidepressants in patients with resistant postpartum depression.