If you are 50 years old and have not had your period for four months and then come back, it may be a normal phenomenon, or it may be abnormal, such as endometrial cancer, cervical cancer and so on. 1. Normal phenomenon: women at the age of 50 have entered the perimenopausal period, when the function of ovaries gradually declines and the hormone level decreases significantly, which will mainly cause changes in menstruation, and there will be a long duration of menstruation, irregular cycles, and the amount of menstruation will be more or less at times, etc. Most women in menopause are not suddenly menopausal. Most of the women in menopause, not suddenly menopause, usually start with menstrual disorders, and then gradually menopause. This is a normal phenomenon. 2. Endometrial cancer: Endometrial cancer is a malignant tumor occurring in the epithelium of the endometrium, which is caused by excessive stimulation of endometrium by oestrogen. The tumor may bleed in the process of growth, which is manifested as postmenopausal vaginal bleeding, and if women have not yet gone through menopause, it will be manifested as increase in the amount of menstruation, prolongation of menstruation period, or menstruation disorders. 3. Cervical cancer: cervical cancer is a malignant tumor originating from the cervix, which is related to high-risk HPV infection. The malignant tumor will erode blood vessels and bleed, which may be manifested as postmenopausal vaginal bleeding in elderly patients. 50 years old four months without menstruation again can go to the hospital for examination, according to clinical symptoms and examination results diagnosis.