Abstract: Objective： To develop a new three-dimensional and reticular intrauterine device （NTDR-IUD） with nickel-titanium （Ni-Ti） and silicone rubber，and to observe its contraceptive effect in rats. Methods：The materials of NTDR-IUD were nitinol wire and silicone rubber. Frame surface was coated by a layer of silicone rubber. Ninety Wistar rats were equally divided into three groups, the test group（placing NTDR-IUD），the surgical control group（operation but no placing NTDR-IUD） and the non-surgical control group. NTDR-IUD was placed into uterus using inserter by lower abdominal incision. After 2 weeks，female rats of three groups were caged together with male rats（female∶male=2∶1）. The contraceptive effects of NTDR-IUD were observed at post-operation 1，2，3，4，5 and 6 months. Ten female rats of the test group were removed the NTDR-IUD from bilateral uterine horns post-operation 3 months. After 2 weeks of removement, these 10 rats and 20 rats from two control groups were caged together with male rats. Results：NTDR-IUD was successfully developed for the three-dimensional and reticular structure. The shape of NTDR-IUD was heart-shaped or inverted pear-shaped. The shape of NTLDR-IUD for animals was spiral structure. After 1，2 and 3 months placing NTDR-IUD，there were not any pregnant，NTDR-IUD were detected by X-ray. There was no pregnancy in 20 female rats of the test group in following 4，5 and 6 months. In the sham operation group，28 of 30 rats were pregnant with average of 9.6±1.0 natal baby-rats per female rat. In the non-surgical control group，29 of 30 rats were pregnant with the average of 9.8±1.2 natal baby-rats. There were significant difference in the number of pregnant rats and natal baby-rats between the test group，the sham operation group and the non-surgical control group（P<0.01）. In the test group，10 rats were pregnant with the average of 9.5±1.3 baby-rats after removed the NTDR-IUD，and 10 rats were pregnant with the average of 9.9±1.5 baby-rats in the sham operation group and the non-surgical control group. There were no significant difference in the number of natal baby-rats between the sham operation group，the non-surgical control group and the test group（P>0.05）. Conclusions：This three-dimensional and reticular IUD has a good contraceptive effect for female rats，and it may be used as a new contraceptive device for women in future.

Key words: Intrauterine devices, Nickel, Titanium, Silicone elastomers, Rats, wistar, Contraception, Animal experimentation