For women who have always had dysmenorrhea and suddenly have a period without pain, if the bleeding is particularly light, it is important to consider whether it is a normal menstrual period or whether it is abnormal vaginal bleeding due to some other cause. For women who are sexually active, it is also important to consider whether the vaginal bleeding is due to pregnancy, which often does not have obvious symptoms of menstrual cramps. However, if a woman has a small amount of bleeding, and at the same time the menstrual cycle is pushed back for a particularly long time, it is necessary to consider that it may be ovarian endocrine dysfunction, resulting in the absence of normal ovulation caused by anovulatory dysmenorrhea manifestations, the bleeding time is usually particularly long, and may even be a spot of bleeding, but during the bleeding period often do not have any pain in the lower abdomen.