CeMCOR: The Centre for Menstrual Cycle and Ovulation Research

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A broad collection of information about menstrual health. Topic areas include fertility, heavy flow, hot flashes, cramps and painful periods, contraception, and more.

“Painful periods are known as cramps. This section looks at what causes cramps and how to ease the discomfort. Doctors call painful periods or cramps “dysmenorrhea.” They are caused by high levels of prostaglandins, a kind of hormone that increases the normal squeezing or contraction of the muscle in the wall of the uterus.”