During a period, the uterus contracts, forcing the lining away from the uterine wall and out through the vaginal opening. These severe pains are caused by uterine contractions.
The discomfort usually starts in the lower abdomen, although it can spread to the lower back, groyne, or upper thighs in some women. Menstrual cramps are usually the worst at the beginning of a period and go better as time goes on.
Menstrual cramps can be relieved with a variety of home treatments, including the following:
Heat
The muscles in the belly can be relaxed and cramps relieved by placing a hot water bottle or heating pad against them.
Heat relaxes the uterine muscle and the muscles around it, reducing cramping and discomfort.
Back discomfort can also be relieved by placing a heating pad on the lower back. Another approach is to relax the muscles in the belly, back, and legs by soaking in a warm bath.