The sudden decrease in breast milk during the month may be related to overwork, nutritional deficiencies and blocked milk ducts, which should be taken seriously in time. 1. Overwork: When a woman is overworked or has not had enough sleep recently, it may lead to a lower secretion of lactin, which in turn may lead to a decrease in the secretion of breastmilk. 2. Nutritional deficiencies: Women who feed their babies during menstruation may suffer from nutritional deficiencies, which may lead to a decrease in milk production. 3. Clogged milk ducts: When a woman has a good nutritional level and a good living condition, she may have enough milk, but the clogged milk ducts may also lead to a sudden decrease in milk production, which is often accompanied by breast swelling and pain and discomfort, and should be taken seriously in a timely manner. In addition, there may be other reasons why breast milk suddenly becomes less during the month, so it is recommended to go to the hospital in time. After a thorough examination to determine the cause of the disease, we will give targeted treatment or therapy.