THE CYCLE PREGNANCY RATE IS NORMAL IN BABOONS WITH STAGE-I ENDOMETRIOSIS BUT DECREASED IN PRIMATES WITH STAGE-II AND STAGE III-IV DISEASE

Objectives: To test the hypothesis that fertility is reduced in baboon s with endometriosis. Design: Prospective controlled follow-up study. Setting: Institute of Primate Research, Nairobi, Kenya. Subjects: Seve nty-one baboons, including 34 controls (normal pelvis) and 37 animals with histologically proven endometriosis (16 spontaneous and 21 induce d). Baboons with endometriosis had minimal (n = 9), mild (n = 14), mod erate (n = 7), or severe (n = 7) disease. Interventions: Seventy-one b aboons were mated during 286 cycles. Main Outcome Measures: Cycle fecu ndity rate, cycle pregnancy rate, cycle abortion rate. Results: Cycle pregnancy rate (excluding spontaneous abortions) was 15% (44/286) and was comparable between controls (19%, 20/104) and baboons with endomet riosis (13%, 24/182). The cycle pregnancy rates were 24%, 10%, 7.5%, a nd 12.5% in animals with minimal, mild, moderate, and severe endometri osis, respectively. The cycle pregnancy rate was significantly lower i n baboons with stage III-IV endometriosis (9%, 6/64) and with stage II disease (10%, 7/73) than in animals with stage I endometriosis (24%, 11/45) or in controls with a normal pelvis (19%). Conclusion: The norm al cycle pregnancy rate in baboons with stage I endometriosis and the decreased cycle pregnancy rate in baboons with stage II and stage III- TV disease suggest that fertility decreases with the stage of endometr iosis in baboons.