Dysmenorrhea means painful menstruation and is classified as primary (from the onset of menstruation) or secondary (due to some physical cause and usually of later onset).

The uterus is a muscle. Like all muscles, it contracts and relaxes. Most uterine contractions are never noticed, but strong ones are painful.

During strong contractions, the uterus may contract too strongly or too frequently, causing the blood supply to the uterus to be temporarily cut off. This deprives the muscle of oxygen, causing pain.

In addition to painful uterine cramping with menses, women with dysmenorrhea may experience nausea, vomiting, diarrhea, headaches, weakness, and/or fainting. Symptoms may vary in severity from cycle to cycle, but generally continue throughout the reproductive years.

Dysmenorrhea can be an incapacitating problem, causing significant disruption in a woman's life each month.