A new experimental three-dimensional, reticular intrauterine device (3-DRIUD) composed of nitinol and silicone rubber

Abstract

Background: The aim of this study was to explore a new three-dimensional, reticular intrauterine device (3-DRIUD) composed of nitinol and silicone rubber and to observe the contraceptive effect of the device in rats.

Study design: Two contraceptive experiments were performed. In the first, female rats underwent bilateral placement of a 20.0-35.0-mm 3-DRUID (experimental group, n=30) via an abdominal incision or a sham operation with no IUD (control group, n=30). Two weeks after the operation was performed, the rats from either group were caged together with male rats. The contraceptive effects of the 3-DRIUD were observed at 1 to 3 months postoperation, after which the 3-DRIUDs were removed. One month after this second operation, the rats from the two groups were again coupled with fertile male rats. In a second experiment, female rats underwent bilateral placement of a 10.0-mm 3-DRUID (n=5) via an abdominal incision or a two-dimensional IUD (2-DIUD, n=20) and mated 1 month after surgery. The single-pipeline IUD was placed in 10 rats, while the enfolded-pipeline IUD was placed in 10 different rats.

Results: In the first experiment, none of the females in the experimental 3-DRIUD group became pregnant (0/30, 0%) after 3 months, compared to 28/30 (93.3%, p<.0001) rats in the control group. After the 3-DRIUDs were removed from the experimental group after 3 months, 27/30 (90%) became pregnant, compared with 29/30 (97%, p>.05). The litter size (mean±SD) did not differ between groups (10.9±1.5 3-DRUID, 11.2±1.1 control, p>.05). In the second experiment, five rats had a 10.0-mm 3-DRUID (which was one third the length of one uterine horn) inserted into the bilateral uterine horns, and three of the five rats became pregnant. All 20 rats were pregnant 1 month after the insertion of the 2-DIUD. Thus, the contraceptive rate for the 2-DIUD group was 0.

Conclusions: The primary contraceptive mechanism effect of the new 3-DRIUD in rodents appears to be a result of occupying physical space in the uterus.