Effect of copper and platinum intrauterine devices on endometrial morphology and implantation in the rabbit.

The response of the rabbit endometrium to the copper IUD was investigated. A plastic IUD bearing copper foil (42 mm2) was inserted into one horn of the rabbit uterus and a physically similar platinum-bearing IUD in the contralateral horn served as a control. The Pt-IUD caused no tissue damage and little if any inflammatory reaction in ovariectomized, oestrous or pregnant animals, whereas the Cu-IUD produced endometrial ulcers in 14 out of 15 does in all hormonal states. The associated inflammation was particularly intense in the pregnant animals in which a unilateral pyometra was usually present. Despite the endometrial trauma produced, the Cu-IUD was only partly effective as a contraceptive agent, 36% of the ova shed from the ovary ipsilateral to the Cu-IUD implanting, compared with 63% of the ova ipsilateral to the Pt-IUD. However, almost half of the implantation swellings in the copper-bearing horns were abnormally small or distorted in shape at 9 days post coitum. The tissue destruction observed in the rabbit endometrium emphasizes the need for careful histological studies of the effect of the copper IUD on the human uterus.