The most reliable way to know if your IUD has shifted is by checking the strings that hang through your cervix. If they feel shorter, longer, or you can’t find them at all, the device may have moved. But string changes aren’t the only clue. About 75% of women with a displaced IUD experience pain and unusual bleeding, compared to just 34% of women whose IUD is sitting in the right spot.
How to Check Your IUD Strings
Your IUD has one or two thin plastic strings (they feel like fishing line) that extend about 2 centimeters through the opening of your cervix. Checking them is straightforward: wash your hands, sit or squat in a comfortable position, and insert your index or middle finger into your vagina until you feel your cervix. The cervix feels firm, similar to the tip of your nose. You should be able to feel the strings poking through with your fingertips.
It’s easiest to locate the strings right before or just after your period, when the cervix sits lower and is easier to reach. If you can feel roughly the same length of string each time you check, your IUD is likely still in position. If the strings suddenly feel much shorter or longer than usual, or if you can feel the hard plastic of the IUD itself, the device has probably shifted.
That said, not finding the strings doesn’t automatically mean something is wrong. Up to 18% of IUD users can’t locate their strings at some point. Sometimes strings curl up around the cervix, get tucked behind it, or were trimmed too short at insertion. A healthcare provider can sort this out quickly with an exam.
Symptoms That Suggest Displacement
Not every displaced IUD causes obvious symptoms. Research on women with embedded IUDs found that about half had no symptoms at all. But when symptoms do appear, they tend to follow a pattern: cramping, abnormal bleeding, or both. In one study, bleeding disturbances turned out to be even more predictive of a malpositioned IUD than pain was. Among women who came in with bleeding complaints, 38% had a displaced device.
Watch for these changes:
- New or worsening cramping, especially if it started within days or weeks of insertion and hasn’t improved, or if cramping returns months after things had settled down
- Heavier or irregular bleeding that’s different from your usual pattern
- Pain during sex that wasn’t there before
- Increased discomfort during your period, which can happen when the IUD presses unevenly against the uterine wall
Pain that lasts more than three days after insertion, and especially pain that continues for weeks, is a red flag. Women who experience this are more likely to have a device that didn’t settle into the right position from the start.
When Displacement Becomes Dangerous
In rare cases, an IUD can push through the uterine wall, a complication called perforation. This happens in roughly 1 in 1,000 insertions. The most common warning sign is missing strings, because once the device migrates through the wall, the strings are no longer accessible. Persistent low abdominal pain that doesn’t resolve is another indicator.
If the device migrates far enough to affect the bowel, you might notice abdominal pain combined with fever and diarrhea, or even rectal bleeding. If it reaches the urinary tract, symptoms can include painful urination, blood in the urine, or repeated urinary tract infections. These scenarios are uncommon, but they require prompt medical attention.
How Doctors Confirm a Displaced IUD
At your follow-up visit (typically scheduled about six weeks after insertion), your provider will check that the strings are visible and the right length. This simple visual check catches many problems early. If the strings look different or can’t be found, the next step is an ultrasound.
Transvaginal ultrasound is the standard first-line tool for evaluating IUD position. It’s quick, doesn’t involve radiation, and can show exactly where the device is sitting inside the uterus. The IUD’s stem shows up clearly on imaging, and three-dimensional ultrasound views can reveal whether the arms of the device are positioned correctly. If the IUD can’t be seen on ultrasound at all, a simple abdominal X-ray can determine whether it’s migrated outside the uterus or has been expelled entirely, since all IUDs are visible on X-ray. In complicated cases where perforation is suspected, CT or MRI scans provide a wider view.
How Common Is Displacement?
Complete expulsion, where the IUD falls out entirely, happens in fewer than 5% of users within the first year. The risk is highest in the first few months after insertion. Partial displacement, where the IUD shifts but doesn’t fully come out, is more common, occurring in roughly 11 to 13% of cases in one clinical trial of postpartum IUD placement.
The main risk factor is a mismatch between the size of the IUD and the size of your uterine cavity. When the device is too large for the space, the uterus contracts against it, which can push it out of position or cause it to embed in the uterine wall. This embedding can actually prevent a full expulsion but tends to cause ongoing discomfort and bleeding.
What Happens if Your IUD Has Moved
If your IUD is confirmed to be out of place, the most common recommendation is removal, especially if you’re experiencing pain or bleeding, or if the displacement could reduce the device’s effectiveness as birth control. The World Health Organization has recommended prompt removal of dislocated IUDs due to risks like bowel injury and chronic pelvic pain. However, more recent guidance suggests that for women who have no symptoms, careful monitoring without surgery can be a reasonable approach.
One important finding: women with malpositioned IUDs are more likely to become pregnant within two years (19.2% versus 10.5% in one study), but not because the displaced device itself fails. In that research, every pregnancy occurred after the IUD was removed or expelled, not while it was still in the uterus. The higher pregnancy rate came from women having the device taken out and not starting another reliable method of birth control right away. So if your IUD is removed because it shifted, make sure you have a plan for contraception before or immediately after the removal.
When to Get It Checked
Check your strings once a month, ideally around the same time in your cycle so you have a consistent baseline. Beyond those routine checks, get an evaluation if you notice any combination of new cramping, bleeding changes, pain during sex, or strings that feel different than they used to. The first few months after insertion carry the highest risk of displacement, so pay closer attention during that window. If you ever feel the hard plastic of the IUD at your cervix or in your vagina, the device is actively coming out and you should contact your provider promptly. In the meantime, use a backup method of birth control until a provider confirms everything is in the right place.