Birth control pills are hormonal medications that cause changes in the body’s endocrine hormones and interfere with the production of abnormal endocrine hormones, which may lead to unclean shedding of the endometrium and cause menstrual dripping. Normally, even if there is an adverse reaction and there is withdrawal bleeding, it will end within 3-7 days. If there is constant dripping bleeding when menstruation is present, it is an abnormal manifestation and should be treated with anti-inflammatory and hemostatic treatment. However, it is necessary to go to the hospital for gynecological ultrasound to determine if there is any echogenicity in the endometrium or endometrial hyperplasia, and to take anti-inflammatory and hemostatic medication according to the results of the examination to avoid prolonged bleeding that may cause infection or even anemia. At the same time, after three days of menstruation, the ultrasound should be repeated to ensure that the endometrium is back to normal.