The effect of ligation or separation between the intrauterine device horn and adjacent ovary on implantation in the hamster.

The purpose of this study was to determine whether the luteolytic action of an intrauterine device (IUD) is suppressed following interruption of the continuity between the IUD uterine horn and the adjacent ovary. After several estrous cycles, a silk IUD was placed in the cervical end of one uterine horn of adult hamsters. The animals were then mated, and on day 6 of gestation the ovary and oviduct contralateral to the IUD were removed and a ligature was placed between the IUD horn and the adjacent ovary. The hamsters were killed on day 9 or day 13 of gestation. Fetal development in the contralateral horn was suppressed on day 13 but not on day 9. In the second study the animals were treated as in the first study except that the communication between the IUD horn and the adjacent ovary was severed completely. The hamsters were killed on day 9 or day 13. On both days 9 and 13 normal fetal development was observed in the control horn; no implantation sites were present in the IUD side. In the control (non-IUD) animals of each study, normal fetuses were present in both uterine horns. The study demonstrates that luteolysis does not occur if there is complete disruption of the communication between the IUD horn and ovary. The study also demonstrates that, since implantation did not occur in the IUD horn with a normally functioning ipsilateral ovary, the luteolytic action of the device is not the prime factor in suppressing implantation in the hamster.