A 45-year-old woman not having menstruation for two months may be caused by pregnancy, menopausal manifestations, ovarian tumors, pituitary tumors and other reasons. 1. Pregnancy: 45-year-old women with good ovarian function, there are mature follicles, coitus during ovulation, sperm and egg meet to form a fertilized egg. Pregnancy estrogen and progesterone levels rise, can appear two months without menstruation. 2. Menopausal manifestations: 45-year-old women in the perimenopausal period, ovarian function declines, the level of stimulation decreases, no ovulation or rare ovulation, irregular menstrual cycles. 3. Ovarian tumor: Ovarian support-mesenchymal stromal cell tumor can cause excessive secretion of androgen in female body and inhibition of hypothalamic-pituitary-ovarian function, resulting in cessation of menstruation. 4. Pituitary tumor: Pituitary prolactinoma, thyroid-stimulating adenoma, growth hormone adenoma, etc. can inhibit the release of gonadotropin-releasing hormone from the hypothalamus, resulting in women not having menstruation for two months. If a 45-year-old woman does not have menstruation, it is recommended that she go to the hospital in time for examination and treatment after clarifying the cause of the disease.