Lifetime prevalence rates of major depressive disorder (MDD) in women are estimated to be as high as 21% (Kessler et al., 1993; Weissman et al., 1993). The postpartum period in particular represents a time of increased vulnerability for women (Cox et al., 1993; O'Hara et al., 1990), though postpartum disorders are often under-recognized and undertreated. Pregnant women generally receive little education about the possibility of depression after delivery, and because symptoms of depression can overlap with common postpartum symptoms, they may go unrecognized. Women may also feel ashamed of having negative emotions at a time when they "should be joyful" and thus not seek professional help.
The DSM-IV defines postpartum depression as a major depressive episode with an onset in the first four weeks following childbirth. Although epidemiologic studies vary in the time frame used to define the postpartum period, ranging from four weeks to six months after delivery, the period of increased risk seems to occur relatively close to delivery. A study by Cox et al. (1993) of 232 postpartum women found that rates of depression were threefold higher in the five weeks after giving birth, but comparable at six months postpartum, when compared to a similarly matched control group of women who had not had a baby within the last 12 months. Wisner et al. (2004a) found that in 51 nondepressed women with a history of postpartum depression, 21 women developed a recurrent postpartum episode when followed for the year after childbirth. Five (24%) of these women experienced depression in the first postpartum month.
Postpartum depression should be distinguished from postpartum blues (commonly known as the baby blues), a relatively common condition that can affect 50% to 80% of women and is characterized by emotional lability, irritability, anxiety and sleep disturbance that usually resolves within two postnatal weeks. Treatment for postpartum blues includes reassurance and validation of the woman's experience, as well as assistance in caring for herself, the home and the baby. However, follow-up of women with postpartum blues is important, as up to 20% go on to develop postpartum depression (Stowe, 1996).
Postpartum depression is the most common psychiatric disorder that occurs in the puerperium, and it affects approximately 10% to 15% of women. Women without a history of major depression have a 10% risk of developing postpartum depression, though the risk of depressive symptomatology may be higher (O'Hara et al., 1990). With a history of major depression, the risk for postpartum depression rises to 25%, and with a history of a prior postpartum depression, the risk of recurrence rises further to 50% (Garvey et al., 1983; O'Hara, 1995). In addition to prior history of depression or postpartum depression, other risk factors for developing a postpartum depression include the following (Beck, 1996; Gotlib et al., 1991; Marks et al., 1992; O'Hara, 1986; Zelkowitz and Milet, 1996):
- depressive symptoms during pregnancy
- family history of depression
- marital difficulties
- ambivalence about the pregnancy
- limited social support and stressful life events.
Symptoms of postpartum depression are consistent with those of major depression that occurs at any other time in a woman's life, though women suffering from postpartum depression often have marked anxiety (Hendrick et al., 2000) and a tendency to ruminate or even obsess over the health and well-being of the baby. Other features associated with postpartum depression include lower incidence of suicidality (Pitt, 1968) and more difficult social adjustment (O'Hara et al., 1990), when compared to MDD. Although symptoms of postpartum depression can be quite distressing, they are often missed due to preoccupation with the baby or because the symptoms are attributed to the natural stress of caring for a newborn. Since sleep disturbances, appetite and weight changes, and fatigue are common to the postpartum period, the Edinburgh Postnatal Depression Scale (EPDS) (Cox et al., 1987), which focuses on nonsomatic symptoms, is a useful screening instrument for postpartum depression. A thorough evaluation is also important, as failure to address even subsyndromal symptoms can result in progression to a major depressive episode and/or cause impairment in psychosocial functioning and interactions with the infant.