Menstruation after 9 months of menopause may be caused by vaginitis, endocrine disorders, drug factors, endometrial cancer and so on. 1. Vaginitis: After menopause, due to the decrease of estrogen secretion, vaginal epithelium shrinks, mucous membrane becomes thin, self-cleaning ability is poor, resistance to bacteria is weak, vaginitis may occur, which is manifested as bleeding, vaginal itching, pain and so on. 2. Endocrine disorders: after menopause, the ovarian mesenchyme can still produce estrogen, and if there is too much estrogen, the endometrium will proliferate and bleed. 3. Drugs: After menopause, women usually do not have menstruation again, but if they take estrogenic drugs, such as caprylestrol, etc., it may cause bleeding. 4. Endometrial cancer: If menstruation occurs after 9 months of menopause, it is necessary to consider whether there is endometrial cancer, which leads to abnormal vaginal bleeding. Besides, it may also be caused by other factors, so patients are advised to go to hospital for consultation and treatment after clarifying the causes.