New aspects of the pathophysiology of endometriosis and associated infertility.

After ovulation, peritoneal fluid contains concentrations of progesterone and of 17 beta-estradiol that are 5 to 20 times higher than plasma concentrations in women with ovulatory cycles but not in women with unruptured luteinized follicles. Since viable endometrial cells were found in the peritoneal fluid of over 50% of women, both with and without endometriosis, a new hypothesis is presented about the etiology of pelvic endometriosis and the association of pelvic endometriosis and infertility: pelvic endometriosis could be the consequence of infertility caused by the unruptured luteinized follicle.