Increased Incidence and Recurrence of Recent Corpus Luteum Without Ovulation Stigma (Luteinized Unruptured Follicle Syndrome?) in Baboons With Endometriosis

Objective: To test the hypothesis that a recent corpus luteum (CL) without fresh ovulation stigma (OS) can be found with a higher incidence and recurrence in baboons with endometriosis and is associated with a reduced egg recovery rate after uterine flush.

Methods: One hundred thirty-eight laparoscopies were performed in the early luteal phase of 52 cycles in 32 female baboons with a normal pelvis (controls) and of 86 cycles in 21 animals with endometriosis. The incidence and recurrence of a recent CL without OS was studied during each laparoscopy and during the first three laparoscopies in 15 baboons (five controls, ten with endometriosis), respectively. The association between the presence of a recent CL without OS and the egg recovery rate was evaluated during 65 cycles in 21 baboons after uterine flush.

Results: When all 138 laparoscopies were analyzed, the incidence of a recent CL without OS was higher (P < 0.3) in animals with stage II-IV endometriosis (35%) than in those with stage I disease (19%) or controls (11%). Both the incidence (seven of ten) and recurrence (three of ten) of a recent CL without OS were higher in baboons with endometriosis than in controls (zero of five, P < .02) when studied during the first three laparoscopies. Laparoscopies in primates having a recent CL without OS were associated with a lower egg recovery rate (13%) than in animals with recent CL and OS (54%, P = .005).

Concluson: A recent CL without OS was associated with a reduced egg recovery rate and could be found with a higher incidence and recurrence in baboons with endometriosis than in control, suggesting that luteinized unruptured follicle syndrome exists and could contribute to endometriosis-associated subfertility.