Postpartum Depression: Risk Factors and Treatment Options

Dramatic hormonal changes occur during pregnancy and shortly after childbirth, and a number of studies have investigated the contribution of reproductive events to the occurrence of postpartum mood disorders. Estrogens, progesterone, β-endorphin, human chorionic gonadotropin, prolactin and cortisol levels rise during pregnancy, reaching maximum levels near term and declining sharply after birth. To date, studies of these biologic factors have not identified a specific etiologic link between reproductive changes and postpartum mood disorders (Hendrick et al., 1998). Nevertheless, women who develop postpartum depression may be especially sensitive to these reproductive changes. Oxytocin, which rises sharply at delivery to stimulate uterine muscle contraction and promote the release of breast milk, has not been studied in relationship to postpartum depression.

Abnormalities in postpartum thyroid function have also been postulated as contributing to postpartum mood disturbance. Rates of postpartum hypothyroidism are relatively high in the first six months after childbirth, with the rate of thyroiditis reaching 9%, compared to 3% to 4% in the general population (Goldman, 1986). While thyroid dysfunction does not seem to account for most cases of postpartum depression, it may play a role for a subgroup of women. In a prospective study of 303 pregnant euthyroid women, postpartum thyroid dysfunction developed in 21 women (7%) (Pop et al., 1991). Of these 21 women, 38% had postpartum depression that resolved with treatment of the thyroid abnormality. Thus, thyroid dysfunction should be considered in the evaluation of a woman who presents with postpartum depression.

Untreated postpartum depression may impact maternal functioning, mother-infant bonding and family functioning. Mothers who are depressed are at risk for compromised emotional responsivity to their babies, though maternal behavior varies and maternal depression may not have a singular effect on the infant (Weinberg and Tronick, 1998). Some mothers with depression are disengaged and withdrawn when interacting with their infants, while others can be intrusive, displaying anger and interference. Other mothers are able to mobilize themselves sufficiently to interact positively with their infants (Cohn and Tronick, 1989; Weinberg and Tronick, 1998). Maternal behavior may be influenced by variables such as severity of depression and infant temperament. Nevertheless, maternal depression has been associated with adverse effects on infant attachment and behavior (Murray, 1992; Stein et al., 1991) as well as cognitive development (Cogill et al., 1986).

In a review of the literature, Grace et al. (2003) found that the adverse effects of postpartum depression tend to be greater when the depressive episode is severe and prolonged and when it occurs in the context of adversity. They also found that chronic or recurrent maternal depression is more likely to be related to subsequent effects on the child. These findings underscore the importance of early recognition and treatment of postpartum depression.

The treatment of postpartum depression is multifactorial and includes reassurance, suggestions for increased help around the home, psychoeducation, and, in some cases, psychotherapy and/or pharmacologic treatment (Altshuler et al., 2001). Individual psychotherapy can be an essential part of treatment, especially for women with difficulties adjusting to motherhood and/or fears about new responsibilities. Including a woman's partner in at least one or two meetings can be useful for providing information as well as support. For mothers who find themselves feeling isolated, group psychotherapy may also be helpful.

Psychotherapy treatment studies of postpartum depression have demonstrated the efficacy of interpersonal psychotherapy (IPT). A prospective study by O'Hara et al. (2000) of 120 postpartum women with major depression randomly assigned to 12 weeks of IPT versus a waiting list condition control group found that subjects receiving IPT had significantly greater reduction in depressive symptoms and improvement in social adjustment. Thus, IPT may present an alternative form of treatment to pharmacotherapy, especially for women who are nursing.

Pharmacologic treatment studies for postpartum depression are limited and include one double-blind study demonstrating efficacy of fluoxetine (Prozac) or cognitive-behavioral therapy for major or minor depression (Appleby et al., 1997); one open study each for sertraline (Zoloft), venlafaxine (Effexor) and fluvoxamine (Luvox) (Cohen et al., 2001; Stowe et al., 1995; Suri et al., 2001); and one double-blind, placebo-controlled preventive study for sertraline (Wisner et al., 2004b). Approximately 60% of mothers initiate nursing, and most antidepressants are excreted into breast milk. The majority of reports have not described adverse behavioral effects in nursing infants exposed to antidepressants. In a recent analysis of the available data, Weissman et al. (2004) identified 57 studies of maternal plasma, breast milk and/or infant plasma antidepressant levels from nursing mother-infant pairs. They concluded that sertraline, paroxetine (Paxil) and nortriptyline (Aventyl, Pamelor) may be the preferred choices for nursing women. However, the total number of cases reported for any given medication is small, and concern for infant safety must be considered.

The few months after childbirth represent a time when women may be vulnerable to experiencing postpartum depression. Women should be followed during this period, especially if they have a history of depression or depressive symptoms during pregnancy. Treatment should be multifactorial, including consideration of psychosocial as well as pharmacologic options. Adequate recognition and treatment of postpartum depression is essential to the health and well-being of the mother, the infant and the family.