Abstract: OBJECTIVE: To study the teratogenicity of copper-bearing intrauterine device(Cu-IUD) using Sprague-Dawley rats. METHODS： Timed-pregnant rats were divided into 4 groups (24 for each group)，including three treatment groups (0.1，0.3，and 0.9 g/ml，IV) and vehicle control group (NS，IV.). Rats received extract solution of Cu-IUD or vehicle on gestational days (GD) 6 through 15. Body weight and clinical signs of maternal rats were monitored at regular intervals throughout gestation. At termination (GD 20)，pregnant females were evaluated for clinical status and gestational outcome；live fetuses were examined for external appearance，visceral，and skeletal malformation and variations. RESULTS：There were no maternal deaths and no dose-related clinical signs. Maternal weight gain，liver weight，number of corpora lutea，implantation and live fetuses，body length and tail length of fetuses were not affected. IUD did not affect prenatal viability or incidences of fetal malformations or variations. Percent of resorbed embryos in high dose group was significantly higher than that in control group. CONCLUSION：No maternal toxicity and teratogenicity，but toxic effects in early embryo development were found when rats were treated with extract solution of Cu- IUD at a dose of 0.9 g/ml.

Key words: copper-bearing intrauterine device, toxicity on development, teratogenicity