The sudden decrease in breast milk may be related to mental and emotional factors, or it may be caused by blocked milk ducts or malnutrition. 1. Mental and emotional factors: If you have recently been stimulated by some adverse events, resulting in emotional excitement, too angry and anxious, or excessive mental tension and anxiety, it may lead to a sudden decrease in the amount of breast milk, soft milk. 2. Mammary duct blockage: usually due to too much milk, and not in time to empty the milk, easy to lead to the milk in the breast of the stagnant, resulting in the blockage of the mammary ducts, it may make the breast milk suddenly become less, soft milk. 3. Malnutrition: During the breastfeeding period, if you don’t pay attention to a reasonable diet, the body’s intake of nutrients is insufficient, which may affect the secretion of milk, resulting in a sudden decrease in breast milk, the milk is soft and soft. The reason for this is the fact that there are other reasons for this, so you should look for the causes and seek medical attention as soon as possible, if necessary, and be guided by your doctor.