There are many reasons for not having a period for more than three months. If you have had sexual intercourse in the last three months without proper contraception, there is a possibility of pregnancy, and you can use a test paper or come to the hospital to draw blood to determine pregnancy. If an unwanted pregnancy is found, you can choose abortion or medical abortion to terminate the pregnancy. If pregnancy is completely ruled out, it may also be caused by abnormal ovulation in the last three months or endocrine disorders such as polycystic ovary syndrome. In addition, if you have lost weight or exercised strenuously in the last three months, or if you have been traumatized, it may also affect the endocrine axis of the ovaries, thus affecting ovulation and resulting in failure to have a menstrual period as scheduled. It is advisable to have an ultrasound examination of the uterine adnexa and, if necessary, to take progesterone to promote the onset of menstruation.