The design of the copper intrauterine device (IUD) is decades old and can break when it is removed. Researchers studied how to reduce the risk of breaking the IUD during removal and found that slowing the removal process can help.1
“We see breakage reports are going up and up with copper IUDs,” says Mitchell Creinin, MD, study co-author and a professor and director of the Complex Family Planning Fellowship in the department of obstetrics and gynecology at UC Davis Health. “In my experience of 30 years of being a family planning specialist, you see copper IUDs breaking much more commonly. It is still a rare occurrence, but it’s much more common now. The question is — ‘Why?’”
Creinin began to explore the copper IUD’s design by asking engineers to examine the device. “The first thing they said was, ‘Who designed this stupid IUD?’” he recalls. “You don’t create anything in a true T [shape] because that doesn’t have stability.”
For instance, any buildings with a T shape will include angled pieces to support the T. “Engineers never create T angles like that without further support because they break,” Creinin adds. “We used the IUDs and measurements to create models two times the size. They are injection mold models. We did not do the work on actual IUDs because of the high cost — $1,000 products.”
Using the injection mold models, researchers put sensors on the stems and arm intersection. “We approximated the materials as much as we could,” Creinin says. “Because we made them all the same with the same materials, we could get some relative differences and see what load, force, or stress happens at the joint.”
They also wanted to measure the strain and see how stress changes at the joint during removal. “The main thing we were able to show is there is way more stress on the joint in the ParaGard model than in all hormonal IUD models,” Creinin says. “The arms in the copper IUD [form] a true T, and you can bend them down. As you pull them out, they bend up like a U shape, which puts more stress on the actual junction.”
By contrast, hormonal IUDs are made for the arms to bend up when inserted and bend back up and fold in when removed. This puts much less force on that junction, Creinin explains.
When copper IUDs break, it is always at the junction where the stem and arms come together, Creinin says. “Typically, it has to be retrieved if [the patient] ever wants to get pregnant,” he notes. “Sometimes, it can be done easily in the office, but sometimes it gets stuck in the wall of the uterus.”
Researchers do not know whether the breakage is more likely to occur when the IUD is left in place for so long. What they could see is that the IUD changes as it is removed. It becomes deformed, Creinin adds.
Creinin and colleagues tested the effect of speed in removing the IUD and found that removing it faster could make it more likely to break. “We feel this suggests to [providers] that when they remove a copper IUD, they should do it slowly,” he says. “They think if they can get it out faster, it’s easier for the patient, but if you do it faster, it is more likely to break.”
While the study shows that a copper IUD could be created in a way that is less likely to break during removal, it would be costly to try to change the current design. “If you’re going to change the frame, you need completely new studies, and it’s very expensive,” Creinin says. “It takes tens of millions of dollars to bring it to market. If you change the frame, you have to do a study for 10 years if you want it to be a 10-year device.”
Improving contraception designs is a tradeoff between what would be optimal for patients and what is feasible for research and production.
“The risk of breakage is really low, but our goal in looking at these engineering outcomes is not to say, ‘This is dumb’ — it’s to say we can learn to minimize the risk of breakage,” Creinin says. “This research gives us some knowledge to minimize that risk [and] remove it a little more slowly. Faster is not better.”
For years we have been teaching clinicians this message: Everything in the process of IUD insertion can be done slowly and gently — AND should be done slowly and gently, says Robert Hatcher, MD, MPH, professor emeritus of gynecology and obstetrics at Emory University School of Medicine in Atlanta. Now we should add the same slowly and gently message for clinicians being taught to perform IUD removals, he says.
REFERENCE
- La Saponara V, Wan S, Nagarkar B, et al. Understanding the mechanical behavior of intrauterine devices during simulated removal. Contraception 2024;133:110399.
