Suddenly less breastmilk may be due to insufficient sucking, malnutrition, poor mood, mammary gland blockage and other reasons. 1. Insufficient sucking: usually give the baby less frequent breastmilk, not able to suck milk effectively, the body’s lactogen secretion is reduced, which may lead to breast milk suddenly become less. 2. Malnutrition: usually excessive dieting or picky eating, breastfeeding to drink less soup food, body malnutrition will lead to breast milk suddenly less. 3. Poor mood: prolonged anxiety, depression and poor mood during breastfeeding can lead to endocrine disorders, which can also lead to a sudden decrease in breast milk. 4. Mammary gland blockage: During the breastfeeding period due to milk stagnation, mastitis caused by the mammary gland blockage, the milk can not be smoothly discharged out of the body, can also lead to breast milk suddenly less. There are a lot of reasons for this, and in serious cases, it is advisable to go to the hospital for a checkup.