Depression is the leading cause of disease-related disability among women in the world. In particular, women during their reproductive years are at high risk for major depression (MDD) (Robins et al, 1991). Perinatal depression, defined as depressive episodes that occur either during pregnancy or within the first 6 months postpartum, can have devastating consequences for both the woman experiencing it as well for her children and family (Marmorstein et al, 2004; Flynn et al, 2004).

Studies have demonstrated that perinatal depression has a prevalence rate of at least 10%, making it one of the most common complications of both the prenatal and postpartum period (Yonkers et al, 2001; Gaynes et al, 2005, Dietz et al, 2007). One of the primary risk factors for the development of postpartum depression (PPD) is the onset of depressive symptoms during pregnancy. Depression during pregnancy, also called "antenatal depression" has been associated with low maternal weight gain, increased rates of cigarette, alcohol and other substance use, ambivalence about the pregnancy and overall worse health status (Zuckerman et al, 1989; Suri et al, 2007; Orr et al, 2007). Other risks of untreated depression during pregnancy include the risk of ongoing depressive illness in the mother into the postpartum period, which may impair bonding between the mother and child, as well as the potential risk of impaired cognitive, emotional and social development in the child (Murray et al, 1999).

The first three months postpartum appear to be the most vulnerable period for the appearance of maternal depressive symptoms (Stowe et al, 2005; Munk-Olsen et al, 2006).

Baby Blues versus Postpartum Depression

Although most women will have some mild mood and anxiety symptoms in the first few days to weeks postpartum (the "baby blues"), these symptoms usually resolve spontaneously. More severe and persistent mood and anxiety symptoms in the postpartum period should arouse suspicion of the syndrome of PPD. The initial onset of PPD is usually within the first month of the postpartum period. Symptoms of PPD can differ in important ways from those of routine major depression (MDD) (i.e. depression that occurs in times outside of pregnancy or postpartum).

Symptoms of Postpartum Depression:

• Feeling sad, depressed, and/or crying a lot
• Intense anxiety, rumination, obsessions
• Loss of interest in usual activities
• Feelings of guilt or worthlessness
• Feeling incompetent or inadequate to cope with the new infant
• Fatigue, irritability, sleep disturbance
• Change in appetite
• Poor concentration
• Sleep problems (not being able to sleep even when the patient is sleeping, or wanting to sleep all the time).
• Excessive worry about the baby's health
• Suicidal thoughts
• Thoughts of wanting to hurt the baby.

Classic features of PPD include severe anxiety, agitation, difficulty making decisions, and suicidal thoughts or thoughts of hurting the newborn (Bernstein et al, 2008). PPD is also characterized by symptoms classically seen in major depressive disorder including feelings of being overwhelmed, feelings of guilt or worthlessness, tearfulness, changes in appetite, difficulty sleeping (even when the baby is sleeping), difficulty concentrating, and loss of interest or pleasure in activities. Because the mother's ability to function and attend to the child is impaired, PPD has been associated with lower quality interactions between mothers and their children (Stein et al, 1991), missed pediatric appointments and greater use of emergency department services (Flynn et al 2004), higher levels of psychiatric disturbances among children (Murray et al, 1989) and greater child insecurity in attachment relationships (Mamorstein et el, 2004).