An intrauterine contraceptive system may include a contraceptive intrauterine device, a retrieval thread permanently attached to the intrauterine device and an insertion device for inserting the intrauterine device into a uterus. The system may also include a release thread releasably coupled with the intrauterine device. The intrauterine device may be deployable out of a distal end of the insertion device and may be configured to change from a delivery configuration when housed in the insertion device to a deployed configuration when deployed in a uterus. The retrieval thread and the optional release thread may be at least partially housed within the insertion device during insertion of the intrauterine device into the uterus. The release thread may extend from the intrauterine device through the insertion device to an attachment point at or near a proximal end of the insertion device.