The phenomenon of stomach cramps when menstruation does not come is considered to be related to pregnancy, pelvic inflammatory disease, premenstrual syndrome and other factors. 1. pregnancy factor: for normal sexual life of women, if you do not do a good job of contraceptive measures, may cause delayed menstruation, accompanied by the phenomenon of small stomach swelling, and unwanted pregnancy. 2. Pelvic Inflammatory Disease (PID): This is a common infectious disease of the reproductive tract, especially in fertile women who are sexually active, which not only affects the normal flow of menstruation, but also causes stomach cramps and pain. 3. Premenstrual Syndrome (PMS): mainly occurs before the onset of menstruation, and usually has cyclical recurring symptoms, such as bloating and swelling of the stomach, chest swelling and pain, which can be relieved after the onset of menstruation. There may also be other reasons why you don’t have your period, so we recommend that you go to the hospital in a timely manner, complete the examination to determine the cause of the problem, and then give targeted treatment or therapy.