The main reasons for irritability during breastfeeding are the following: 1. endocrine disorders are the most common reasons, because the rapid changes in endocrine secretion during breastfeeding, such as the magnitude of changes in sex hormones and thyroid hormones are relatively large, which can easily cause the mood of pregnant women to change at any time, so it is easy to make people irritable and unhappy. 2. it may be caused by stress. 3. It may be caused by some conflicts or contradictions, especially bad relationship with mother-in-law, husband and wife, or failure to establish a secure attachment with children or infants in the process of bringing up children, which may also make pregnant women irritable. The problem is that the mother-in-law has a bad relationship with her mother-in-law, the couple has a bad relationship, or they have not established a secure attachment with the child or the baby.