DISAPPEARANCE OF THE OVULATION STIGMA IN BABOONS (PAPIO-ANUBIS, PAPIO-CYNOCEPHALUS) AS DETERMINED BY SERIAL LAPAROSCOPIES DURING THE LUTEAL-PHASE

Objective: To investigate how long an ovulation stigma remains visible as determined by serial laparoscopies performed during the luteal pha se in baboons. Subjects and Setting: Sixteen female baboons with a nor mal pelvis (n = 6) and with endometriosis (n = 10) housed at the Insti tute of Primate Research, Nairobi, Kenya. Interventions: Fifty-six lap aroscopies were carried out before ovulation (n = 7) and serially duri ng the luteal phase (n = 49; 3 +/- 1 per baboon): 1 to 2 days (n = 2), 4 to 5 days (n = 15), 8 to 9 days (n = 11), 12 to 13 days (n = 12), a nd 16 to 17 days (n = 9) after ovulation. Main Outcome Measure: During each laparoscopy the ovaries were screened systematically for the pre sence and size of an ovulation stigma and/or corpus luteum (CL). Resul ts: When the laparoscopy was done within 5 days after ovulation, a fre sh ovulation stigma was observed in all nine baboons with a normal pel vis or minimal endometriosis, but only in four of seven animals with m ild to severe disease. If a fresh ovulation stigma had been observed w ithin 5 days after ovulation (n = 13), it gradually became smaller but remained visible 8 to 9 days after ovulation in 91%, at 12 to 13 days after ovulation in 75%, and at 16 to 17 days after ovulation in 50% o f the primates. Conclusion: If a fresh ovulation stigma was observed i n baboons within 5 days after ovulation, it diminished in size but rem ained visible up to 8, 12, and 16 days after ovulation in 91%, 75%, an d 50% of animals, respectively. Therefore, diagnostic laparoscopies fo r the detection of an ovulation stigma in baboons should be performed in the early luteal phase.