Fertility following cervicectomy and utero-vaginal anastomosis in the rabbit.

Abstract

The role of the cervix in maintenance of pregnancy was investigated follow-ing unilateral resection of the cervix and utero-vaginal anastomosis in 23 rabbits. Fertility and morphological studies were made to compare the operated and contralateral intact uterine horns. In 5 animals autopsied 2 days post coitum, 52.6% of the eggs ovulated from the ovaries on the operated side were fertilized compared with 92.9% on the intact side. At laparotomies or autopsies performed 9 days post coitum (18 does), 93 of 104 (89.3%) ova released from the ovaries on the intact side and 55 of 106 (52.1%) ova on the operated side became implanted. There was no marked difference in the spacing and size of implants between the operated and intact uterine horns, but distribution of implants in the operated horns had shifted slightly toward the vagina compared to the controls. When allowed to go to term, pregnant does delivered young normally from the intact uteri; but in the operated uteri dystocia was noted frequently. Morphological observations revealed no abnormality in the endometrium of either uterine horn following operation, but there was occasional inflammatory reaction in the newly formed vaginal portion. The present findings indicate that the rabbit cervix does not always play a significant role in holding embryos or fetuses in the uterine cavity once fertilization has been accomplished.