An IUD that becomes embedded in the uterine wall has partially pushed into the muscular layer of the uterus rather than sitting freely inside the cavity where it was placed. The consequences range from barely noticeable to seriously dangerous, depending on how deeply the device has burrowed and whether it stays put or keeps migrating. Most embedded IUDs cause pelvic pain, unusual bleeding, or strings that can no longer be felt, but a fraction produce no symptoms at all and are discovered incidentally on imaging. The condition almost always requires removal, though the method and urgency vary widely.
The Spectrum From Malposition to Perforation
Not every out-of-place IUD is embedded, and not every embedded IUD has perforated the uterus. These are distinct points on a continuum. An IUD can simply shift downward toward the cervix (malposition) without penetrating tissue. Embedding specifically means part of the device has pressed into or through the inner lining and into the myometrium, the thick muscular wall of the uterus. Full perforation means the device has passed entirely through the wall and entered the abdominal cavity.
Clinicians classify these situations by how far the device has traveled. A widely used framework divides the anatomy into three compartments: the uterine cavity, the myometrium, and the peritoneal cavity outside the uterus. An IUD sitting partly in the cavity and partly in the muscle wall is a partial perforation. One that has passed all the way through into the abdomen is a complete perforation.1PubMed. Complete and partial uterine perforation and embedding following insertion of intrauterine devices. I. Classification, complications, mechanism, incidence, and missing string A large cohort study defined partial perforation as an IUD embedded in the myometrium as seen on imaging or during removal, while complete perforation meant the device was found free in the pelvis or abdominal cavity.2PubMed Central. Absolute risks of uterine perforation and expulsion associated with intrauterine devices The practical takeaway: embedding is often the midpoint of a process that can stop there or progress further.
Symptoms You Might Notice
The most common signs of an embedded IUD are pelvic pain, abnormal bleeding, and missing strings. In a study of patients sent for ultrasound evaluation of their IUD, pain was the leading reason (about half of cases), followed by strings that could not be located (roughly two in five) and bleeding (about one in seven).3PubMed. Does the type of intrauterine device affect conspicuity on 2D and 3D ultrasound? Among patients who presented with bleeding, more than a third had a malpositioned device, suggesting bleeding is a particularly telling clue that something has shifted.
Pain from an embedded IUD can range from a dull, chronic ache to sharp cramping. If the device’s arms have dug into the muscle wall, the uterus may contract around them, producing cramps that feel different from normal period pain. Bleeding patterns vary too: you might experience spotting between periods, heavier-than-usual flow, or prolonged bleeding that does not follow your typical cycle.
Some embedded IUDs produce no symptoms whatsoever, particularly when the degree of embedding is mild. A device whose side arms have edged slightly into the myometrium may go undetected for years unless imaging is done for an unrelated reason. This silent embedding is more common than many people realize, which is one reason clinicians emphasize follow-up visits after insertion.
Why IUDs Become Embedded
Embedding can happen at the time of insertion or develop gradually afterward. A “primary” perforation occurs during the insertion procedure itself, when the instrument or the device pushes through the uterine wall. A “secondary” or delayed perforation is thought to result from the uterus contracting around the device over time, slowly pressing it into the muscle.4Ovid. Medicolegal Aspects of an Unusual Uterine Perforation With Multiload-Cu 375R
The biggest risk factor identified in large studies is having an IUD inserted during the postpartum period, especially while breastfeeding. A major multisite cohort study found that among postpartum individuals with breastfeeding data, the five-year cumulative incidence of uterine perforation was about 1.4%, and breastfeeding independently raised the risk.5PubMed. Intrauterine device-related uterine perforation incidence and risk (APEX-IUD): a large multisite cohort study The likely explanation is that breastfeeding suppresses estrogen, which thins the uterine wall and makes it easier for the device to press through. The postpartum uterus is also still involuting, meaning it is shrinking back to its pre-pregnancy size, and that remodeling process may make the tissue more vulnerable.
Device fit matters as well. An IUD that does not conform well to the shape and size of a particular uterine cavity is more likely to cause pain, bleeding, embedding, or expulsion.6PubMed Central. Use of frameless intrauterine devices and systems in young nulliparous and adolescent women: results of a multicenter study A smaller uterus (common in people who have never been pregnant) may be at higher risk simply because the standard T-shaped frame is relatively large for the cavity. Uterine anatomy is surprisingly variable from person to person, and a mismatch between device and cavity size can set the stage for the arms of the device to press into tissue they were never meant to contact.
How Embedding Is Diagnosed
When you report symptoms like pain, bleeding, or missing strings, the first step is almost always an ultrasound. Ultrasound serves as the front-line imaging tool for evaluating IUD position.7Ultrasonography. Ultrasonography of intrauterine devices Standard two-dimensional ultrasound can usually tell whether the IUD is in the cavity, but it has limitations when the embedding is subtle. In one study, about a quarter of IUDs evaluated by ultrasound turned out to be malpositioned.3PubMed. Does the type of intrauterine device affect conspicuity on 2D and 3D ultrasound?
Three-dimensional ultrasound offers a significant advantage for detecting embedding that standard 2D imaging misses. A study of consecutive patients found that about one in six had IUD arms located abnormally within the myometrium, and this was only detectable on the 3D reconstructed view.8PubMed. Three-dimensional ultrasound detection of abnormally located intrauterine contraceptive devices which are a source of pelvic pain and abnormal bleeding If you are experiencing symptoms and a 2D scan looks normal, a 3D scan or a different imaging approach may be the next logical step.
When the IUD cannot be seen in the uterus at all on ultrasound, a plain abdominal X-ray can confirm whether the device is still somewhere in the body (ruling out silent expulsion) and give a rough sense of where it has migrated. In some cases, CT or MRI may be used to pinpoint the exact location before a surgical plan is made.
How an Embedded IUD Gets Removed
Removal methods depend on how deeply the device is embedded and whether it is still partly accessible from inside the uterine cavity.
For partial embedding where some portion of the IUD or its strings can still be reached, office-based hysteroscopy is often the first approach. A thin camera is passed through the cervix, allowing the clinician to see the cavity directly and locate the device. One technique uses a hysteroscope alongside an IUD hook, providing direct visualization while applying enough traction to pull the device free.9PubMed. Office hysteroscopy to guide intrauterine device hook use for the removal of a deeply embedded intrauterine device When the IUD is so deeply buried that it is not visible at all through the hysteroscope, clinicians have used portable X-ray imaging during the procedure to guide tissue removal around the device until enough of it is exposed to grasp and extract.10Annals of Case Reports. Fully Embedded IUD: Hysteroscopic Management Using X-ray
If the IUD has passed entirely through the uterine wall into the abdominal cavity, hysteroscopy will not work because the device is no longer inside the uterus. In these cases, laparoscopic surgery (minimally invasive, through small incisions in the abdomen) is the standard approach. Most experts now advise removing any IUD found in the peritoneal cavity, even in patients without symptoms, because of the risk of the device adhering to or damaging surrounding organs over time.11PubMed Central. Laparoscopic removal of a migrated copper IUD causing pelvic abscess: a case report Laparoscopy is preferred over open surgery for stable, asymptomatic patients, while open surgery (laparotomy) is reserved for cases involving significant organ damage or complicated adhesions.12PubMed Central. Laparoscopic removal of migrated intrauterine device embedded in intestine
Newer techniques aim to reduce tissue damage during removal. Ultrasound-derived 3D modeling has been used to map the precise position of a deeply embedded IUD before surgery, allowing surgeons to plan smaller incisions and minimize trauma to the uterine muscle. This approach also reduces the risk of accidentally entering the uterine cavity during the removal, which matters for people who want to preserve fertility.13Journal of Minimally Invasive Gynecology. Cost-Effective 3D Modeling for Precise Complex Removal of a Deeply Embedded IUD – a Novel Approach to Surgical Optimization
When the Device Migrates Beyond the Uterus
A fully perforated IUD does not always stay near the uterus. Once in the abdominal cavity, it can migrate over months or years, sometimes ending up far from where it started. Levonorgestrel-releasing IUDs (hormonal types) seem particularly prone to traveling. In a study comparing lost hormonal and copper devices, two-thirds of the hormonal IUDs were found embedded in the omentum (the fatty tissue draping over the intestines), and four of the six had migrated to the upper abdomen, far from the pelvis. None of the copper IUDs in the study showed this kind of discrepancy between their expected and actual locations.14Contraception. Lost levonorgestrel IUD: diagnosis and therapy The reason is not entirely clear, but the hormonal device’s smoother surface and the suppressive effect of levonorgestrel on surrounding tissue may allow it to slide more freely once it exits the uterus.
Migration into or near the intestines is the most feared complication. A migrated IUD can become entangled in loops of bowel, forming adhesions that develop silently over years. In an extreme case, a device that had migrated decades earlier eventually strangulated a segment of small intestine, causing tissue death that required emergency open surgery to remove roughly a meter of necrotic bowel.15PubMed Central. Case Report: Strangulated intestinal obstruction due to chronic migration of an intrauterine device (IUD): a 30-year latent complication Cases like this are rare, but they underscore why current expert consensus leans toward removing any IUD found outside the uterus rather than adopting a wait-and-see approach.
Similarly, a case report described a 68-year-old woman who had lived with a forgotten IUD for decades. She presented with chronic pelvic pain and postmenopausal bleeding, and during surgery, the device was found embedded in the cul-de-sac (the space between the uterus and rectum).16PubMed Central. Retained Lippes Loop Intrauterine Device (IUD) in a Woman With Post-menopausal Bleeding and Chronic Pelvic Pain These long-latency cases illustrate that a migrated device does not become inert just because years pass without obvious trouble.
Can You Leave an Embedded IUD Alone?
This is a legitimate clinical question, and the answer is nuanced. If the IUD is partially embedded but still mostly within the uterine cavity, and the patient has no symptoms and no desire for pregnancy, some clinicians will monitor rather than immediately intervene. Asymptomatic patients with a displaced hormonal IUD can sometimes be managed expectantly, though the pregnancy risk is likely higher with a malpositioned device.17Clin Obstet Gynecol Reprod Med. Malposition and displacement of intrauterine devices–diagnosis, management and prevention If symptoms develop, or if the device shifts further, removal and replacement with a better-fitting device or a different contraceptive method becomes the plan.
For IUDs that have fully perforated into the abdominal cavity, the traditional stance was more cautious: asymptomatic patients were sometimes left alone because surgery carries its own risks. Some clinicians have argued that under certain circumstances, conservative management may benefit asymptomatic patients with extrauterine IUDs.18Contraception. Extrauterine mislocated IUD: is surgical removal mandatory? However, the pendulum has swung. Today, most experts recommend removing any IUD found in the peritoneal cavity because of the unpredictable long-term risk of adhesions and bowel complications.11PubMed Central. Laparoscopic removal of a migrated copper IUD causing pelvic abscess: a case report The earlier debate has not been fully resolved, but the trend in clinical practice favors removal.
What Embedding Means for Contraceptive Protection
An embedded IUD may or may not still prevent pregnancy, depending on its position. If most of the device remains in the uterine cavity and only the arms have pressed slightly into the muscle, contraceptive effectiveness is probably reduced but not eliminated. A hormonal IUD continues releasing levonorgestrel locally even when partially embedded, so some contraceptive effect persists. A copper IUD relies on the copper surface interacting with the uterine environment, and if the device has shifted substantially, that interaction is compromised.
If the IUD has fully perforated into the abdomen, it offers no contraceptive protection at all. You can become pregnant with a perforated IUD, and you may not realize the device has left the uterus until a pregnancy is discovered or an imaging study happens to find the device in the wrong place. This is why missing strings should always be investigated promptly: if the strings have retracted because the device has embedded or perforated, you could be unprotected without knowing it.
What the Uterus Does in Response to the Device
Regardless of whether an IUD is properly positioned, the uterus mounts a foreign-body response to its presence. The tissue lining the cavity becomes infiltrated by immune cells, particularly white blood cells and macrophages, which move through the tissue and up to the surface layer.19PubMed. Endometrial morphological changes in IUD users: a review This inflammatory response is actually part of how copper IUDs work to prevent pregnancy. But when the device is embedded, the inflammatory reaction occurs deeper in the uterine wall, potentially causing more pain and contributing to the cramping that many people with embedded devices report.
Over time, the myometrium can form scar tissue around the embedded portions of the device, essentially walling it off. This can make delayed removal more difficult, as the IUD becomes encased in fibrous tissue rather than sitting in a space where it can be easily grasped. It is one reason why clinicians prefer to address embedding sooner rather than later when it is discovered, even if symptoms are mild.
Device Design and the Embedding Problem
The standard T-shaped IUD frame is a rigid structure designed to hold the device in place against the uterine walls. That rigidity is a double-edged sword: it resists expulsion but also means the device exerts pressure on the endometrium and underlying muscle, especially if the cavity is small or unusually shaped. The arms of the T are the parts most commonly found embedded in the myometrium on 3D imaging.8PubMed. Three-dimensional ultrasound detection of abnormally located intrauterine contraceptive devices which are a source of pelvic pain and abnormal bleeding
Frameless IUD designs were developed partly to address this issue. These devices anchor to the uterine fundus with a small knot rather than relying on a rigid frame to stay in place. Because they lack the T-shaped arms, there is no lateral pressure against the myometrium. Frameless copper IUDs use solid tubular copper sleeves rather than wire wrapped around a frame, which also increases the copper surface area and the device’s lifespan.20PubMed Central. Considerations on a new, frameless copper-releasing intrauterine system for intracesarean insertion and its future clinical significance: a review Frameless designs are not widely available in every country, but they represent one approach to reducing the size-mismatch problem that contributes to embedding.
Pain During Removal of an Embedded IUD
Standard IUD removal is quick and usually causes only brief cramping. Removing an embedded device is a different experience. Difficult removals are associated with significantly more pain, with patients reporting pain scores well above what is typical for a routine removal.21PubMed. Prospective Evaluation of Ease and Difficulties of 869 Cases of Intrauterine Devices Removals If office-based removal is attempted for an embedded IUD, your clinician should discuss pain management options beforehand, which may include local anesthesia, cervical numbing agents, or pre-procedure anti-inflammatory medication. When removal requires hysteroscopy or surgery, the procedure is typically performed under sedation or general anesthesia.
The emotional dimension deserves mention too. Many people describe anxiety about IUD removal that goes beyond the physical discomfort, especially if the insertion itself was painful or if they have been living with symptoms for a long time before the embedding was diagnosed. If you are facing removal of an embedded IUD, asking your provider specifically about the planned approach, the pain control strategy, and what to expect during recovery can help you feel more prepared.
How Embedding Differs From Expulsion
Expulsion and embedding are essentially opposite failure modes. In expulsion, the uterus pushes the device out, usually through the cervix. In embedding, the device moves in the other direction, pressing into or through the uterine wall. Both result in a device that is no longer in its intended position, and both reduce or eliminate contraceptive protection. But the implications are quite different. An expelled IUD is usually noticed (you may feel or see it), and while inconvenient, it poses no ongoing risk once it is out. An embedded IUD can go undetected and may require medical or surgical intervention to address.
Interestingly, the same risk factors that increase expulsion risk (recent childbirth, a uterine cavity that does not match the device dimensions) also appear in the embedding literature. The underlying theme is that the fit between the device and the individual uterus matters enormously for whether the IUD stays where it belongs.