Ovulatory bleeding is caused by irregular shedding of the uterine lining due to fluctuations in the patient’s estrogen level during the peri-ovulatory period. Before ovulation a woman’s estrogen level is very high, and after ovulation a woman’s estrogen level drops, and the endometrium appears to retreat due to the drop in estrogen level, manifesting itself as a small amount of vaginal bleeding. Generally, ovulation bleeding occurs about 14 days before the next menstrual period, the amount of vaginal bleeding is very small, coffee-colored or brown, there is no pain in the lower abdomen, there is no odor of secretion, not accompanied by vulvar itching, the vaginal bleeding lasts for a short period of time, and the vaginal bleeding is usually self-cleaning after 3-5 days.