Menstrual cramps are caused by contractions in the uterus, which is a muscle. If the rate of contraction is high, it can exert pressure on the surrounding blood vessels blocking the supply of oxygen to the muscle tissue of the uterus. When the muscle briefly loses its supply of oxygen, the pain is felt. Depending on what causes painful periods, they can be divided into two types- primary dysmenorrhea and secondary dysmenorrhea.
HOW IS PAINFUL PERIODS DIAGNOSED?
Common cramps start at the beginning of the period and continue for two or three days.