Dysmenorrhea is a common gynecologic disorder affecting up 50 % of menstruating women. Primary dysmenorrhea refers to menstrual pain without pelvic pathology, whereas secondary dysmenorrheaid defined as painful menses associated with underlying pahtology.

The pain of primary dysmenorrhea ususally begins a few hours or just after the onset of a menstrual period and may last up t0 48 or 72 hours. With suprapubic cramping, and may be accompanied by lumbosacral backache, pain radiating down the anterior thigh, nausea, vomiting, diarrhea, and rarely syncopal episodes.

The suprapubic region may be tender to palpatioon, bowel sounds are normal, and there is no upper abdominal tenderness and no abdominal rebound tenderness. Bimanual examinatians at the time of the dysmenorrhea episode often reveals uterine tenderness; however, severe pain with movement of the cervix or palpation of the adnexal struaction is absent. The pelvic organs are normal in primary dysmenorrhea.

The cause of primary dysmenorrhea is increased endometrial prostaglandin production. These compounds are found in higher concentration in secretory endometrium than in proliferative endometrium. The decline of progesterone levels in the late luteal phase triggers lytic enzymatic action, rsulting in a release of phospholipids with the generation of arachidonic acid and activation of the cyclooxygenase pathway. Women with primary dysmenorrhea have higher uterine tone with high-amplitude contractions resulting in decreased uterine blood flow. Vasopressin concentrations are also higher in women with dysmenorrhea.