Cramps or pain that occur before your period are known as dysmenorrhoea. It is a common part of the menstrual cycle that is usually felt as muscle cramps in the lower part of your abdomen. These period pains are caused by contractions of the muscular wall of the uterus, also known as the womb. There are continuous contractions in the womb but they are usually so mild that most women don’t feel them. However, these contractions can happen more vigorously during your menstruation which allows the womb lining to shed away as part of your monthly period. These contractions can become so intense that it causes the womb to press against the blood vessels nearby, temporarily cutting off the oxygen flow and blood supply to the womb. This lack of oxygen in the womb is what causes cramping or pains as the womb tissues release chemicals which will trigger pain. While this is happening, the body also produces prostaglandins, the hormones that encourage the womb muscles to contract, causing increasing levels of pain.