This kind of sadness is understood by anyone. Many women make this cry before their period comes, why is this? Does it matter in the end? Why does this happen? We have to start with a mysterious substance, that is hormones, and the breast is the tissue regulated by this mysterious substance. One is before ovulation, which stimulates the formation of luteinizing hormone and promotes ovulation, and the other is before menstruation, when the ducts of the mammary glands grow under the influence of estrogen, and the breast tissue grows and expands like chicken blood; in addition, the level of progesterone rises before menstruation, and the endothelial cells of the lobules of the ducts become enlarged. Therefore, before the onset of menstruation, many women will noticeably feel their breasts swell, become larger, tense and firm, and even have varying degrees of pain and tenderness, which many women say they cannot even touch. After menstruation, the estrogen and progesterone levels decrease rapidly and the breast gland returns to its normal level like a deflated balloon, and the above changes occur again and again before the next menstruation. Every menstrual cycle, the mammary glands go through a process of hyperplasia and rejuvenation, which most women can tolerate without any treatment. So if you have regular premenstrual breast tenderness, there is no need to worry. If you are still unsure, come to the hospital for a medical checkup, and if it is just a simple breast enlargement, then there is no need to be overly nervous.