Menstrual cramps may be caused by identifiable problems, such as endometriosis or uterine fibroids. Treating any underlying cause is key to reducing the pain. Menstrual cramps that aren't caused by an underlying condition tend to lessen with age and often improve once a woman has given birth...over-the-counter pain relievers, such as ibuprofen or naproxen sodium , at regular doses starting the day before you expect your period to begin. Prescription nonsteroidal anti-inflammatory drugs (NSAIDs), such as mefenamic acid, also are available. If you can't take NSAIDs, acetaminophen may lessen your pain...consult nearest gynecologists they will do the needful.