Two forms of dysmenorrhea can be identified: 1.Primary dysmenorrhea not related to any definable pelvic lesion. This usually begins with the first ovulatory cycles beginning in most cases before the age of 20. Primary dysmenorrhea is associated with nausea in 50% of patients, vomiting in 25% of patients and stool frequency in 35% of patients. The pain is low and crampy recurring in waves that probably correlate with uterine contractions. The pain usually occurs a few hours before bleeding, comes to a peak intensity within a few hours, and dissipates within 1-2 days. It generally occurs over the midline, and is relieved by the onset of good menstrual flow.
2.Secondary dysmenorrhea related to the presence of pelvic lesions secondary to organic pelvic disease such as endometriosis, salpingitis and PID (pelvic inflammatory disease), post surgical adhesions, etc. Secondary dysmenorrhea begins up to a few days before menstruation and lasts several days after the onset of flow. Often it is on one side and it does not characteristically peak and diminish as clearly or quickly as primary dysmenorrhea. Its onset is later in life in women who have not had primary dysmenorrhea, however it can be superimposed onto a pre-existing case of primary dysmenorrhea. The IUD may cause such pain problems.