The amount of breast milk is not fixed and changes with the time of pregnancy and delivery, and it is also related to the nutritional status of the pregnant woman. During late pregnancy, pregnant women’s breasts often secrete a small amount of colostrum, and after delivery, when the baby begins to suckle, the amount of lactation increases rapidly. Under normal circumstances, the amount of colostrum varies between 2-20ml each time during the first 3 days after delivery, the average total milk production is about 175ml on the 2nd day after delivery, and the milk volume increases rapidly to about 500ml on the 3rd-4th day after delivery, and normal milk production is achieved 10-14 days after delivery. In the following months, a healthy baby consumes about 700-800ml of breast milk per day. Low milk production indicates a malnourished mother. A mother with relatively poor nutrition usually produces about 500-700ml of milk per day for the first 6 months, about 400-600ml for the second 6 months and 300-500ml for the second year, usually because the mother did not store enough fat in her diet during pregnancy to provide energy for the lactation period. When the mother is extremely malnourished, milk production often decreases or even stops altogether. The mother must pay attention to supplementation and timely supplementation with high quality protein, calcium and other elements.