Does it hurt the whole time you are on your period? Most females who get cramps on their period only have the pain for the first few days of their period. Doctors think that cramps are caused by prostaglandin, a chemical that causes the muscles of the uterus to contract. Many girls and women find that over-the-counter pain medications (like acetaminophen or ibuprofen) can relieve cramps, as can taking a warm bath or applying a warm heating pad to the lower abdomen. Exercising regularly throughout the monthly cycle can help lessen cramps. I find that exercise really works for me. Especially if I'm doing ab exercises I won't get cramps at all. Also the older I've gotten the cramps have lessened. I hope this helps.