According to the American Psychiatric Association (APA) (1994), a
postpartum mood episode, which may include psychotic features, is one whose
onset is within four weeks of birth. According to Beck (1999b), PPMD can occur anytime in the postpartum year, but is most frequently seen in the first three
months. Depressed women often suffer covertly without confiding their sadness
or negative feelings because of shame, guilt and the stigma that prevents them
from seeking help. These disorders are severely underdiagnosed. More than half
of women identified by screening to have PPMD had not been identified as
depressed by their health care provider (Hearn et al., 1998).