The reason for the sudden decrease in milk production during breastfeeding may be due to psychological factors, improper diet, pregnancy and so on. 1. Psychological factors: overwork, long-term late night, emotional fluctuations and other reasons. It may cause a decrease in the amount of milk. 2. Improper diet: unbalanced diet, or insufficient diet, protein is too low, insufficient water intake, it is easy to lead to a gradual decrease in the secretion of milk. 3. Pregnancy: Unexpected pregnancy during the breastfeeding period increases the secretion of estrogen and progesterone, and a large amount of estrogen will have the effect of returning to the milk, in addition to the higher progesterone during pregnancy, which will also affect the secretion of milk. Avoid overwork in your daily life, calm your emotions, and when you have a sudden decrease in milk production during breastfeeding, you must have a timely examination to identify the specific cause of the disease and carry out reasonable and standardized treatment.