The length of time spent breastfeeding does not have a significant impact on the size of the breast, and there is no scientific basis for this view. The main reason why some women’s breasts become smaller after breastfeeding for a long time may be the following: 1. normal physiological phenomenon: because of the high secretion of prolactin in the body during breastfeeding, the mammary gland alveoli and mammary gland ducts are better developed, which can promote the secretion of milk, and thus the performance of breast enlargement; after the end of breastfeeding, there is no milk secretion in the breasts of women, so the phenomenon of smaller breasts may occur, which is normal. This is a normal physiological phenomenon, and mothers need not be overly anxious. Maternity can wear the right size, comfortable material breastfeeding bra or breast massage, after the end of the breastfeeding period, its breast shape and size usually does not change significantly; 2, weight loss: some women in the breastfeeding period will end, in order to maintain the body weight loss, and fat is an important component of the chest, excessive weight loss may lead to smaller breasts. Therefore, 6 months after childbirth, the body basically recovered, according to the recovery of the body to start regular fitness exercise, but should pay attention to the intensity and frequency of exercise gradually, focusing on the upper limbs and chest exercise, such as stretching and chest expansion exercises, breast massage exercises, etc., can help the chest to play a certain role in shaping, and thus prevent the occurrence of smaller breasts.