Rabbit uterine contractile activity patterns in the presence of an intrauterine device (IUD) were monitored with extraluminal contractile force transducers. These patterns were recorded daily during estrus, immediately following coitus, and through the first 16 days postcoitus. The IUD induced local fetal degeneration. Extraluminal contractile force transducers influenced neither nidation nor normal fetal development. Smaller decreases in uterine motility were recorded from the IUD containing horn during the first 6 days and subsequent 10 days postcoitus.