Why will postpartum depression: First, psychological reasons, many mothers are very uncomfortable with the upcoming responsibility of motherhood, and the baby may cry, sick, feeding, etc. all make the mother produce psychological pressure, which leads to tension, anxiety, depression. Second, physiological reasons, during pregnancy, female estrogen and progesterone growth is relatively fast, but after delivery estrogen and progesterone reduced to the previous level, a substantial decline may lead to depression. Environmental factors, such as family economic conditions, housing environment and the relationship between mother-in-law and daughter-in-law during the menstruation period, may lead to depression. Fourth, may be related to the mother’s own experience, if the mother has a history of depression, miscarriage or single-parent families, etc., will aggravate the postpartum depression.