Postpartum depression is a depressive disorder that occurs in mothers after childbirth. Its manifestations are the same as other depressive disorders, with depressed mood, lack of pleasure, sadness and crying, worrying, timidity and fear, irritability, irritability and anger, and in severe cases, loss of self-care and ability to care for the baby, pessimism and despair, and self-injury and suicide. If recognized early and treated actively, the prognosis is good. During pregnancy and delivery, women experience a series of physiological, psychological and environmental changes, and postpartum mental health problems are very common, among which postpartum depression is the most common one. The causes of postpartum depression are mainly the following: Biological factors: 1. Rapid changes in hormone levels During pregnancy, the level of estrogen and progesterone in the body of pregnant women increases for a long time, estrogen has a variety of neuromodulatory functions, and the sudden withdrawal of estrogen after delivery, the fluctuation of estrogen and the continuous lack of estrogen may lead to depression; thyroid function is affected by a variety of factors during pregnancy, and thyroid hormone levels are also affected after delivery. Thyroid hormone level also changes after delivery, and thyroid dysfunction is also related to postpartum depression. 2. Abnormalities in central neurotransmitter metabolism and corresponding receptor function, abnormal neurotransmitter content and reduced functional activity in the synaptic gap of the brain, involving neurotransmitters such as 5-hydroxytryptamine, dopamine and norepinephrine. A history of previous depressive episodes and a positive family history are also important risk factors. Psychosocial factors: Such factors are closely related to the occurrence of postpartum depression and mainly involve the following: adverse life events, lack of good social support, fear before delivery, delivery complications, poor or bad relationship between husband and wife, poor or bad relationship between mother-in-law and daughter-in-law, family economic tension, child feeding style, weaker personality or neurotic characteristics, advanced maternal age, and lack of health education during pregnancy. Postpartum depression in the first week after delivery, about 50-75% of women have mild depressive symptoms, 10%-15% suffer from postpartum depression, and the incidence of depressive disorder in the first month after delivery is three times that of non-delivery women. So the incidence of postpartum depression is still relatively high.