The vast majority of women’s periods clear in 3-7 days, with the average being 5-6 days. If the bleeding occurs on the 5th or 6th day after the menstruation, which is basically the time of ovulation, it is clinically considered as ovulatory bleeding. The main reason is that during ovulation, the estrogen and progesterone in the body are at relatively low levels and the endometrium loses the support of estrogen and progesterone, resulting in withdrawal bleeding, which is much less than the amount of menstruation and clears on its own in 3-5 days and is not accompanied by lower abdominal pain. If it is accompanied by lower abdominal pain, it is often caused by pelvic inflammation or endometriosis. It is recommended that a clinical gynecological examination or ultrasound be done to find out whether there is pelvic inflammation and whether there are foci of endometriosis in the pelvis.