Menstrual drenching without stomach pain may be caused by anovulatory abnormal uterine bleeding, intrauterine device, endometrial polyp, uterine fibroids and other reasons. 1. Anovulatory Abnormal Uterine Bleeding: common in adolescent girls and perimenopausal women, due to hypothalamic-pituitary-ovarian dysfunction, the ovaries do not ovulate. The endometrium is influenced by a single estrogen and lacks progesterone antagonism. Due to the lack of progesterone, the endometrium is unable to cause cyclic shedding, resulting in the loss of the normal cycle of menstruation, menstrual dribbling, and most of them do not have lower abdominal pain when they are not accompanied by inflammation. 2. Intrauterine device (IUD): The main side effects of IUD placement are irregular uterine bleeding, prolonged menstrual period and irregular menstrual flow, etc. Most of them do not have lower abdominal pain. 3. Endometrial polyps: the specific etiology is unknown, and may be related to factors such as elevated estrogen levels and endometritis. Endometrial polyps can cause prolonged menstruation, irregular menstruation and other symptoms, without lower abdominal pain. 4. Uterine fibroids: the etiology is unclear and may be related to elevated estrogen and progesterone levels and genetic factors. Ischemic necrosis of submucosal fibroids can cause irregular vaginal bleeding and menstrual bleeding without lower abdominal pain. Patients with irregular menstruation are advised to consult a doctor for a complete examination under the guidance of the doctor to identify the cause of the disease and provide treatment.