In 25 rabbits (Group E) endometrium from the right uterine horn was transplanted onto the peritoneum. In 25 rabbits (Group C) fat was transplanted. After a recovery period of 12 weeks the does were mated, and killed 24 h later. In Group E the implants had changed into cysts of 5\p=n-\15mm in diameter. Histological examination revealed endometrial glands and stroma in every specimen. Periadenexal adhesions did not develop in any animal. No differences were found between Groups C and E in the

more »

... er of corpora lutea, the recovery rate, the fertilization rate and the transport of fertilized ova. These findings indicate that endometrial implants in the rabbit have no influence on the ovulatory mechanism, the pickup function of the oviduct, the fertilization rate or on the transport of fertilized ova. Taking into account the restrictions of a rabbit model, it is suggested that the decreased fecundity in mild endometriosis in the human may be caused by disturbances in post-fertilization events, i.e. development of the pre-implantation embryo or implantation.