Birth control pills can get rid of those painful cramps and muscle spasms you get while on your period. "They will frequently lessen the cramping that women have with their menses," says Landa. "The main reason for this is that cramping occurs when the uterus contracts to try to expel the blood clots and tissue that are expelled with menses." Because bleeding is usually lighter with the birth control pill from a decreased build up of uterine lining, there is less uterine contraction needed, which can bring relief.