While biological, psychosocial and cultural theories have been investigated the exact causes of postpartum depression are unknown.
Biological
Postpartum dysregulation of the thyroid gland is another possible cause of depression. This condition is also linked to fatigue. The thyroid gland regulates several hormones and drops production dramatically after birth, returning to normal functioning in three sequential stages. The first stage, which can last from 3 to 6 months, is hyperthyroidism where the thyroid goes into overdrive, resulting in anxiety and insomnia. The second phase is hypothyroidism where production is slowed, causing lethargy and weight gain. The final stage in recovery is when output reaches prepregnant levels. Investigations into the relationship between thyroid dysregulation and postpartum depression have yielded contradictory results and no firm link has been proven. Therefore, treatment is considered only when symptoms are severe enough to interfere with daily living.
There has been research on specific hormones and postpartum depression. Hormones levels change dramatically throughout pregnancy, delivery, and the postpartum period. Researchers are examining a possible relationship between sudden shifts in hormone levels and postpartum depression.
Causes, though, may be found in social or psychological factors.
Psychosocial
Psychosocial and emotional factors seem to be related to this condition, acting as stressors and impacting a woman's self-esteem. New mothers are concerned about levels of support and prolonged postpartum depression is linked to lack of social support.
Sleeplessness and fatigue are common complaints. Giving birth taxes a woman's strength, and it can take several weeks to recover. A cesarean delivery is major surgery and requires even more recovery time. Combined with the energy spent caring for a baby around the clock as well as tending to other responsibilities, it is no surprise new mothers suffer inadequate rest. The resulting fatigue may increase a woman's vulnerability and be an added risk for depression.
A major factor in postpartum depression is lack of support from others. New mothers need comfort and support during pregnancy and after delivery. She also needs help with household chores and childcare. Such support may be lacking for a single mother or for a woman with few family nearby.
The mother's changing role may feed the feeling of "inadequacy." Women with depression sometimes view these changes differently than do non-depressed women.
The mother's attitude toward her pregnancy may be important when evaluating risk. It is common for a woman to feel doubt about pregnancy, particularly when unplanned. A greater incidence of depression is reported among women who were ambivalent about pregnancy.
Weight gain during pregnancy can also affect self-esteem and increase a risk of depression.
Mixed feelings sometimes arise from a woman's past. Early loss of one's own mother or a poor mother-daughter relationship might cause her feel unsure about her new baby. She may fear that caring for the child will lead to pain, disappointment, or loss.
Feelings of loss, such as loss of freedom and control are common and can add to depression.
Breast-feeding problems can also lead to depression. New mothers need not feel guilty if they stop. The baby can be well nourished with formula.
Women who have their babies by cesarean birth are likely to feel more depressed and have lower self-esteem than women who had spontaneous vaginal deliveries.
Mothers with pre-term babies often become depressed. An early birth results in unexpected changes in routines and is an added stressor.
A baby with a birth defect makes adjustment even more difficult for parents.
The length of time the mother spends in the hospital may be related to her emotional well-being. There is evidence that early discharge increases the risk of developing depression.
The birth of a first child is a particularly stressful event for new mothers and seems to have a greater relationship to depression than do the birth of a second or third child.
Cultural Aspects
Cross-cultural studies indicate that the incidence of postpartum depression but not psychosis is much lower in non-western cultures. These cultures seem to provide the new mother with a level of emotional and physical support that is largely absent in western society. In more traditional cultures there is greater recognition of the demands of motherhood. Thus, the new mother receives assurance that the discomfort she is experiencing will pass and that she will not have to face those feelings alone. In contrast, the absence of such support has been reported in the U.S. Only 18 percent of new mothers receive more than two weeks assistance with housework and 20 percent reported help with child care beyond the first week.
