Computer analysis of etiology and pregnancy rate in 636 cases of primary infertility.

Since the rate of pregnancy is a function of time, conventional pregnancy rates (number of patients achieving pregnancy per number of patients treated) are inadequate for counseling unless the follow-up period is specified. To overcome this problem, the expectancy of pregnancy for 636 cases of primary infertility was calculated with the assumption that the patients were followed up indefinitely. The overall "conventional" pregnancy rate was 38%, whereas the overall expectancy of pregnancy was 64%. Endometriosis was found to be the most common factor, comprising 25% of the cases, with a pregnancy rate of 31% and an expectancy of 52%. The expectancy of future pregnancy in a patient who has not achieved pregnancy by a given time is presented for each etiologic factor. This paper also presents a comparison of expectancies of pregnancy by different treatments, which may be helpful in selecting appropriate therapy.