Usually, women’s breasts are symmetrical in size from left to right. If they are asymmetrical, it is caused by pathological or physiological, either temporarily or permanently. 1.Physiological. It is usually caused by the different sensitivity of both breasts to estrogen and progesterone. Usually, the side that is more sensitive to estrogen and progesterone will grow faster and will be larger than the other side of the breast. The side that is not sensitive to hormones will grow more slowly. As the body grows and develops, both breasts will slowly become symmetrical. When this state occurs, it is recommended that more weight can be extracted using the side with slower breast development, and regular massage and hot compresses on the breast can speed up the growth of the breast. 2, pathological. Usually caused by excessive secretion of estrogen in the organism. The two mammary glands respond differently to hormones, resulting in one breast being large and one breast being small. In particular, we should be alert to the presence of masses in the side with large breasts, such as tumors, inflammatory lesions, etc., which can cause asymmetry on both sides of the breast and require specialist consultation. If you are breastfeeding, you should pay attention to the balance of both sides when you let your baby suckle, don’t always give one side to your baby to eat milk. If there is a big difference in the size of both sides of a woman’s breasts, surgery can be performed for aesthetic reasons. However, breast enlargement or breast shaping surgery is not recommended for women in their adolescent years to avoid affecting breast development. There are different sizes of breasts and also different treatments according to medical advice.