Reasons for bleeding after menstruation: 1. Bleeding after menstruation may be pregnancy, preterm miscarriage or ectopic pregnancy abnormal bleeding as menstruation. In this case, further examination of blood HCG or gynecologic ultrasound is needed to determine the next step of treatment. 2, also seen in patients with uterine scar diverticulum formation after cesarean section, for which further examination of gynecologic ultrasound and hysteroscopy, if necessary, is needed to clarify the diagnosis. 3, also seen in patients with endometrial polyps and submucosal myomas, further examination of gynecologic ultrasound, gynecologic examination and hysteroscopy, if necessary, is needed, If the patient has endometrial lesions, a diagnostic curettage will be performed to determine the next step of treatment according to the postoperative pathology. 5.