Shortly after the birth of a child, many women experience a period of dysphoria known as postpartum blues. It has been estimated that up to 80% of postpartum women experience symptoms of negative mood and affect that sharply contrast with expectations of feeling happy and a sense of accomplishment. These feelings usually remit without intervention. Postpartum depression, however, is a more serious and less common condition that threatens a mother’s emotional and physical health, and the health of her infant.
Postpartum mood disorders encompass a range of clinical symptoms. Interpretation of epidemiological data requires understanding how these disorders are defined diagnostically and in clinical research. First, postpartum depression is not distinguished from major depression except in terms of its timing. A diagnosis of postpartum depression requires onset of a major depressive episode within 4 weeks of delivery. However, most researchers apply the term more liberally and generally consider a major or minor depressive episode occurring up to 12 months postdelivery to fall within the scope of postpartum depression. Minor depression, also called subclinical depression, has no formal diagnosis but is used to label mood disorders presenting with fewer symptoms than required for a diagnosis of major depression. Postpartum minor depression is not to be confused with postpartum blues. Postpartum blues is a milder constellation of symptoms, including depressed mood, emotional lability, insomnia, tearfulness, irritability, and anxiety, usually beginning within the first few days after delivery, and is relatively transient. Despite the somewhat fluid nature of these definitions, postpartum blues is viewed as categorically distinct from postpartum depression. Typically, blues symptoms resolve within a few days and do not require intervention.
Although there are nosological distinctions between postpartum depression and subclinical postpartum depression, the body of postpartum depression research encompasses both clinically significant and subclinical depression and has produced valuable knowledge of epidemiology, risk factors, screening tools, and successful treatments. Therefore, the reader should note that in this entry, postpartum depression refers to both minor and major depression.
Although the prevalence of postpartum depression has been estimated to be 10% to 15%, a more recent study suggests that it is really much lower. In an effort to more accurately quantify the disease burden of depression in new mothers, the Agency for Healthcare Research and Quality and the Safe Motherhood Group conducted a systematic review of postpartum depression literature with the aim of generalizing prevalence to the U.S. population (Gaynes et al., 2005). Included studies were those carried out in developed countries and that used clinical interviews to confirm episodes of major or minor depression from 1 week after delivery to 12 months postpartum. Prevalence estimates ranged from 1.0% to 5.9% for major depression alone, and from 6.5% to 12.9% for major and minor depression. Although prevalence estimates for postpartum depression are similar to the prevalence of depression in women across the life span, much evidence supports the argument that the birth of a child is an especially vulnerable time, and certain factors may lead to a depressive disorder. Physiologic underpinnings and biopsychosocial risk factors are reviewed in the following sections.
Empirical data provide generally limited support for a neurological or endocrinological basis of postpartum depression. Nonetheless, the postpartum period is marked by distinct physiological changes that do not occur with the onset of nonpuerperal mood disorders. Normal pregnancy is characterized by marked elevations in estradiol, progesterone, and cortisol. Following childbirth, these hormones rapidly return to prepregnancy levels. The onset and maintenance of lactation during the postpartum period is associated with rapid increases in prolactin. Despite these changes, the data do not support the hypothesis that the rapid decline in hormone levels is responsible for depression onset (Zonana & Gorman, 2005). With few exceptions, most research has found no relationship between estrogen or magnitude of change in estrogen levels in depressed versus nondepressed postpartum women, and evidence for the relationship between the decline in progesterone and postpartum depression remains contradictory. Change in cortisol levels has also shown an inconsistent relationship to postpartum mood. There is little evidence that lower levels of prolactin are associated with depressive symptomatology. However, studies of breast-feeding and negative mood indicate a potential buffering effect, possibly mediated by the elevations of prolactin and oxytocin in mothers who breast-feed.
Despite these inconsistent data, research continues to examine the possible neuroendocrine underpinnings of postpartum depression. For instance, recent research shows depressed postpartum women to have significantly reduced bioavailability of serotonin compared to nondepressed postpartum women (Newport et al., 2004). Serotonin has a well-established role in the etiology and treatment of depression. It is possible that the precipitous decline in estrogen and cholesterol during the postpartum period, both of which are associated with the synthesis and metabolism of serotonin, may explain these findings. Taken together, these data indicate that further investigation into biological factors is warranted.
Although the proximal cause is not well understood, researchers have identified a number of biopsychosocial risk factors of postpartum depression. Significant postpartum fatigue, postpartum pain, depression history, depression during pregnancy, poor social support, negative events, and stress are all predictors of postpartum depression (Kendall-Tackett, 2005).
Fatigue is a prominent clinical feature of depression. Maternal fatigue during the first postpartum week has been found to predict depressive symptomatology at 1 month. Although other factors contribute to fatigue, inadequate sleep may play an etiological role in the development of postpartum depression. Mothers with no immediate symptoms of postpartum depression who report poor infant sleep patterns are more likely to report significant symptoms of depression weeks later (Dennis & Ross, 2005). Disturbed sleep patterns are often expected with a new infant. The normalcy of reduced sleep throughout the early postpartum period does not, however, invalidate the role it may play in the development of postpartum depression. Objective sleep data is extremely limited in this population because polysomnographic procedures are highly invasive for new mothers. Still, research would benefit from further examining characteristics of sleep patterns in postpartum women (e.g., reduced rapid eye movement latency).
Major depression is also highly comorbid with chronic pain. Although the physical pain women experience during the postpartum period is transient, it is often constant and severe. Types of postpartum pain can arise from a variety of sources including abdominal pain from surgical delivery, breast pain from feeding difficulties, uterine contractions, perineal pain from tears or episiotomies, or lumbar-pelvic pain. Postpartum low-back pain is relatively common. Healthy women with postpartum lumbar-pelvic pain have been found to experience more significant depressive symptomatology than those without pain (Gutke, Josefsson, & Oberg, 2007). Women whose deliveries require instrumental assistance (i.e., forceps or vacuum extractor) or cesarean section tend to report more depression and negative mood symptoms several months postpartum compared to women who deliver normally.
Similar to fatigue, a certain amount of discomfort may be an expected part of postpartum adjustment. But effective postpartum pain management is not impossible. Thorough screening for pain in primary care (using subjective history and objective assessment) would be extremely useful to identify women who are at risk and to develop strategies that target a mother’s specific type of pain.
Evidence from nonpuerperal depression literature strongly indicates that having a history of major depression significantly increases one’s likelihood of developing a subsequent episode. The same risk applies to postpartum women. Among the strongest risk factors for developing postpartum depression is previous experience of depression at any time, not just in relation to a previous childbirth (Robertson, Grace, Wallington, & Stewart, 2004). Consistent evidence also demonstrates that experiencing depressed mood and anxiety during pregnancy significantly predicts postpartum depression. Although postpartum blues is usually expected to remit without intervention, blues symptoms have been found to increase vulnerability to postpartum depression, though effect sizes are small. This relationship may indicate that in some women, blues symptoms persist, become more severe, and develop into depression.
Whether it is a mother’s first or subsequent child, the addition of a new infant creates a substantial shift in roles and responsibilities. The perinatal period is demanding both physically and emotionally. Experiencing inadequate social support during the postpartum period increases risk of depressive symptoms. The most important support often comes from women’s partners, who, in most Western cultures, are expected to share in the responsibility of infant care. It is not surprising that another predictor of postpartum depressed mood is distress within the marital relationship. When social support is not available, particularly during times of stress, depression is also more likely to result.
Experiencing negative life events during the postpartum period increases risk of postpartum depression. Psychological models of depression are often presented within a vulnerability-stress paradigm. O’Hara, Schlechte, Lewis, and Varner (1991) found support for a vulnerability-stress model of postpartum depression; in their study, depression history and measures of social and cognitive vulnerability interacted with life stress, accounting for 19% of the variance in postpartum depression diagnoses. The postpartum period is a time when women are particularly vulnerable to the effects of negative life events and stress, even if stress is brought on by chronic or ongoing situations that were present before the pregnancy. For instance, lower socioeconomic status and economic hardship are chronic stressors that are predictive of postpartum depression, albeit with small effect sizes.
The childbirth experience itself has been found to affect risk of postpartum depression. Childbirth can be an extremely stressful and even traumatic experience for some women. Characteristics of negative birth experiences include lack of control and inadequate support, both positively correlated with postpartum depressive symptomatology. Incidence of adverse birth outcomes, including prematurity, also contributes to postpartum depressive symptoms. Research has suggested that underlying hormonal processes of stress-related depression and preterm delivery are largely overlapping, in turn suggesting that a preterm delivery may be predictive of postpartum depressive symptomatology (Halbreich, 2005). While ensuring the health and normal development of the infant is paramount, the impact of preterm delivery on a mother’s mental health should not be overlooked.
Although the temporal precedence differs among physiologic and psychosocial variables and postpartum depression, research clearly illustrates the importance of identifying and addressing risk factors to prevent the onset of a major depressive episode.
In early research, postpartum depression was described as a culture-bound illness, largely absent from non-Western countries because of protective features such as postpartum social structure, recognition of a new mother’s vulnerability, required rest, recognized social status, and practical support from family, friends, and other caregivers (Posmontier & Horowitz, 2004). However, the so-called absence of postpartum depression in non-Western cultures may be largely a myth, driven by culture-specific presentations of depression. In non-Western cultures, depression may be more commonly expressed via physical complaints. Moreover, certain social support or traditional customs, such as family members moving in, can be intrusive and may not necessarily protect against postpartum depression.
A growing body of cross-cultural research provides substantial evidence that postpartum depression occurs in numerous non-Western cultures at rates that are similar to or higher than in Western countries, including, Korea, Japan, India, Costa Rica, Taiwan, Chile, South Africa, Nigeria, and the United Arab Emirates (see for a review, Halbreich & Karkun, 2006; Ponsmontier & Horowitz, 2004). Research also shows that risk factors are largely similar cross-culturally, with the exception that the impact of infant gender on postpartum depression was more significant in countries that place higher value on male children (e.g., China, Turkey, and India). Rates of postpartum depression among ethnic minority women do not appear to differ from general prevalence estimates, with factors such as history of psychiatric illness, stress, and impaired support contributing to overall risk. In general, findings conclude that there is universality to postpartum depression, although not all cultures share the same label for it, if it is labeled at all.
Future research should further explore cross-cultural aspects of postpartum depression, particularly as it applies to ethnic minority populations in Western countries and the process of acculturation. The relationship between acculturation and postpartum depression in U.S. populations has not been clearly identified, mostly because this research is limited in its assessment of acculturation, focusing only on language proficiency and childhood exposure to U.S. culture. Future research should benefit from the work of the Transcultural Study of Postnatal Depression (TCS-PND), which has developed reliable and culturally valid measures that will enhance research of postpartum depression across different health care systems and countries (Asten, Marks, Oates, & the TCS-PND Group, 2004).
Accurate screening is an essential first step to identifying women who are at risk of having postpartum depression. Most of the research described in this entry utilized screening tools to assess depressive symptomatology. Screening instruments vary in their ability to detect major and minor depression, both in terms of sensitivity (proportion of true positives) and specificity (proportion of true negatives). Two instruments specific to the postpartum period are the Postpartum Depression Screening Scale (PDSS) and the most commonly used Edinburgh Postnatal Depression Scale (EPDS), which include fewer somatic symptoms than the Beck Depression Inventory (BDI). In general, the PDSS and EPDS seem to be more sensitive than the BDI and the Center for Epidemiological Studies Depression Scale (though estimates of sensitivity are variable for each measure), and all four instruments provide high degrees of specificity for detecting both major and minor depression (Gaynes et al., 2005).
Two logical opportunities for routine depression screening are the standard 4- to 6-week postpartum check-up and the infant’s first pediatric visit. Despite these opportunities and the availability of validated screening tools, screening for postpartum depression in primary care settings occurs for fewer than half of new mothers. Even when women are screened positively for postpartum depression, appropriate follow-up is not always incorporated into clinical practice. Screening and appropriate clinical follow-up are key components of regular postpartum care that may prevent postpartum depression onset, or identify women who may benefit from treatment. The next section focuses on current available treatment modalities for postpartum depression.
Similar to nonpuerperal depressive disorders, approaches to treating postpartum depression can consist of a range of methods, including dietary modifications, supplements, exercise, and community interventions (e.g., support groups), as well as traditional pharmacotherapies and psychotherapies. What follows are recent developments in pharmacologic and psychotherapeutic treatment of postpartum depression.
Women make countless lifestyle adjustments during pregnancy in order to prevent adverse outcomes. Many mothers are cautious about what can safely be consumed, and for those who choose to breast-feed, concerns persist after the baby is born. These concerns can lead to hesitation when it comes to pharmacologic treatments that have demonstrated efficacy in the treatment of depression. Depressed postpartum women are more likely than nondepressed women to stop breastfeeding earlier, and some do so in part because of concerns surrounding the effects of antidepressants on infants. Antidepressants can be an effective method of depression treatment and do not necessarily require termination of breastfeeding. These treatments may be especially indicated for cases of severe major postpartum depression but also in cases of minor postpartum depression.
Most drugs enter human breast milk by passive diffusion, with concentration levels rising in maternal milk as they rise in the mother’s plasma, but most antidepressants have been found to pose minimal risk of adverse outcomes in neonates. Both tricyclics and selective serotonin-reuptake inhibitors including amytriptyline (Elavil), nortriptyline (Pamelor), imipramine (Tofranil), sertraline (Zoloft), and paroxetine (Paxil) are not found in quantifiable amounts in breast-fed infants, and risk of adverse effects is extremely small (Wisner, Perel, & Findling, 1996). Fluoxetine (Prozac), citalopram (Celexa), and buproprion (Wellbutrin) are typically recommended only when the potential benefit to the mother outweighs a moderate risk to younger infants. Despite the availability of relatively safe pharmacologic options, some mothers may wish to avoid medications. For these women, psychological treatments are another option.
Psychotherapeutic treatments are an efficacious approach to postpartum depression for women who do not wish to take medications or as an adjuvant therapy. Cognitive behavioral therapy (CBT) and interpersonal psychotherapy (IPT) have both been shown to be just as effective as medication in treating postpartum depression (see for a review, Chabrol & Callahan, 2007). Similar to CBT, IPT is a time-limited treatment in which individuals are asked to focus on problem areas particularly significant to postpartum women, including role transitions and interpersonal disputes. The goal of most postpartum depression treatments is to reduce depressive symptomatology and enhance the mother’s adjustment to her new role. However, researchers have recently argued that effectively treating depression is not adequate to improve the maternal-infant relationship.
Effects of postpartum depression on new mothers pose a threat to their psychological, emotional, and physical health. Research also shows a range of deficits in infants of depressed mothers that are attributable to impaired mother-infant interactions. Evidence that treatments targeting maternal symptoms also extend benefits to infants is extremely limited. Infant attachment security, behavior problems, and temperament have been found to be unaffected by symptom-relieving treatment such as IPT. In contrast, psychotherapies that focus on the mother-infant interaction, promote maternal sensitivity, responsivity, and nonintrusiveness, and seek to improve maternal self-efficacy have been found to reduce levels of depression while also increasing infant cognitive ability, emotion regulation, and attachment security (Nylen, Moran, Franklin, & O’Hara, 2006). Some of these therapies add a home-based component, likely to be helpful for depressed mothers who lack energy and motivation to attend regular therapy sessions.
Postpartum depression poses a significant risk to a new mother’s physical and emotional health, as well as her ability to care for herself and her infant. Recent epidemiological data for both major and minor depression suggest that postpartum depression afflicts 6% to 13% of new mothers at various times during the first postpartum year. Biopsychosocial risk factors for developing postpartum depression include fatigue, pain, history of postpartum depression, depression or anxiety during pregnancy, stress, inadequate support, and marital dissatisfaction. Although a clear neuroendocrine basis of postpartum depression remains uncertain, extreme physiological changes that take place in the immediate postpartum may have an etiological role. Recent research has indicated that women across nearly all cultures experience postpartum depression. Finally, availability of screening measures and therapies provide multiple options for treating depression while accounting for the specific needs of new mothers and their infants. The addition of a mother-infant interaction focus to treatment may enhance outcomes beyond the remission of symptoms that most effective treatments provide.
See also: Chronic Pain; Cognitive Behavioral Therapy; Hormones
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