The reasons for early or low menstruation are as follows: 1, not normal menstrual flow, a small amount of bleeding will occur during ovulation, and it will be about 14 days earlier than normal menstruation; 2, patients with endometrial exfoliation insufficiency and low estrogen level, irregular vaginal bleeding will also occur, this bleeding is spotty, small and irregular; 3, patients with uterine adhesions have less menstrual flow; 4, those with luteal insufficiency, after ovulation This condition also leads to early menstruation; 5. As women age, the ovarian reserve function decreases, follicle-stimulating hormone rises, and they start to recruit follicles and ovulate early during the luteal phase, and their menstruation becomes shorter, resulting in less menstrual flow. This condition tends to lead to decreased fertility in patients because the endometrium is not ready after the follicles grow, resulting in the follicles and endometrium being out of sync, leading to decreased fertility. However, if such advanced women remove the eggs early to form embryos when there is follicular growth and freeze the embryos when the lining is suitable, it can improve the woman’s chances of conception.