There are many reasons for the decrease of menstruation, and the most common reason is endocrine disorder. If the normal menstruation is normal, and the amount of menstruation occasionally decreases, it can be observed temporarily. If menstruation is still more than one third less than the original three months later, it means that the amount of menstruation is reduced. This may be due to endocrine disorder, abnormal ovulation, poor follicular development, low estrogen level, and thin endometrium. Therefore, the amount of menstruation will decrease when menstruation comes. In this case, we need to go to the hospital to check the six sex hormones and thyroid hormones. We need to adjust menstruation according to the results of the check. If there is a decrease in menstruation after induced abortion, it may be caused by endometrial damage caused by induced abortion or uterine adhesion. At this time, we can go to the hospital for hysteroscopy. If there is adhesion, It can be separated under hysteroscopy. After the operation, you need to eat a lot of estrogen to promote the growth of endometrium, and then your menstruation can return to normal.