Incidence of pelvic endometriosis in Rochester, Minnesota, 1970-1979.

To the authors' knowledge, the incidence pelvic endometriosis in the general female population has not been previously reported. The purpose of the present study was to determine the incidence rate of diagnosed pelvic endometriosis among white females of reproductive age (15-49 years) in Rochester, Minnesota, during 1970-1979. Incidence rates were prepared first with histologically confirmed cases alone and then with the successive inclusion of progressively less certain cases: surgically visualized, clinically probable, and clinically possible. The overall incidence of pelvic endometriosis more than doubled (from 108.8 to 246.9 cases per 100,000 person-years) as the definition of a case was extended from histologically confirmed cases alone to all cases. Age-specific incidence rates increased in successive age groups through age 44 and then declined for women 45-49 years of age. Methodological problems in the definition and ascertainment of incident cases of pelvic endometriosis are described in detail.