A period is when a woman's body releases tissue it no longer needs.Every month or so, the uterus lining gets thicker to prepare for a fertilized egg if the woman becomes pregnant. Period cramps happen due to a hormone-like substance, prostaglandins, which causes the uterus walls to contract and then shed its lining, resulting in your period. If prostaglandin levels are higher, more pain is often associated with the cramps.
