There are many reasons for not having menstruation for four months. For women of childbearing age, the most common reason for not having menstruation for four months is endocrine dysfunction, which is often seen in polycystic ovary syndrome, hyperprolactinemia, and abnormal thyroid function, all of which may lead to not having menstruation for four months. If menopausal women do not have menstruation for four months, it may be due to the phenomenon of ovarian function decline or failure, that is to say, entering the perimenopausal period, and it is possible that after a period of time, menopause will occur. Therefore, if you do not have menstruation for four months, you must go to the hospital for examination as soon as possible, first of all, do ultrasound, and then check the sex hormone six and thyroid hormone, according to the results of the examination to stop menstruation treatment, if the results of the examination of the perimenopausal period is the failure of the ovaries, which is a kind of natural phenomenon that does not need to be treated.