The intrauterine device (IUD) is widely used globally as a long-acting reversible contraceptive method due to its high efficacy, cost-effectiveness, and convenience (1). Despite its excellent safety profile, it is not without risks, which include contraceptive failure (intrauterine or ectopic pregnancy) and the less common complication of uterine perforation (2–4).

Intrauterine device migration is a serious but relatively rare complication, with an estimated incidence ranging from 1 to 2 per 1,000 cases (2, 5). Risk factors associated with IUD migration include insufficient operator experience, abnormal uterine position (such as extreme anteversion or retroversion), and inappropriate timing of insertion–defined as placement within 4 weeks after delivery, especially after vaginal delivery, or while breastfeeding–which significantly increases the risks of both complete expulsion (adjusted risk ratio 5.3–8.3) (6) and uterine perforation (incidence ≈ 1–2 per 1,000 insertions) (7). After migrating into the abdominal cavity, the displaced IUD may cause erosion to adjacent organs, such as the omentum, intestines, or bladder (5, 8, 9). Given that this process often follows a chronic and insidious course, patients may remain asymptomatic in the early stages until serious complications–including intestinal obstruction, bowel strangulation, or fistula formation–develop and bring the condition to clinical attention (8, 10). If the IUD migrates into the bladder and acts as a nidus for secondary vesical calculus formation, patients may present with refractory urinary irritation symptoms and hematuria (9, 11). Since empirical antibiotic therapy typically yields no significant improvement, the diagnosis is often established at this stage (11). Management of a displaced IUD requires comprehensive clinical evaluation, and surgical removal is generally indicated. Available approaches include hysteroscopy, cystoscopy, laparoscopy, or laparotomy, depending on the location and associated complications (12–14).

This report presents a case of a woman with two previous cesarean deliveries whose IUD migrated into the bladder and formed stones, which were ultimately successfully removed via cystoscopy without lithotripsy. This case aims to enhance clinical awareness of this rare entity, elucidate the pathophysiological link between cesarean scars and IUD migration, and discuss the role of individualized minimally invasive management strategies.

This case report exemplifies a rare and clinically significant complication of long-term IUD use: chronic transmural migration culminating in bladder perforation and secondary stone formation. The principal findings encompass the intravesical migration of a copper IUD, the formation of a sizable calculus encasing its intravesical arm, and the successful resolution through a multidisciplinary team MDT, minimally invasive surgical approach.

A paramount risk factor identified in our patient was her history of two previous cesarean sections. The resultant scar in the lower uterine segment, a recognized locus of structural weakness often termed a “cesarean scar niche,” likely offered diminished resistance to penetration and guided the IUD’s trajectory anteriorly toward the bladder (15). Recent quantitative data underscore this risk: in a pooled analysis of 7,661 postpartum IUD insertions the complete expulsion rate was 3.8% after cesarean delivery but 14.8% after vaginal delivery (adjusted RR 4.57; 95% CI 3.49–5.99) (6), while the APEX-IUD cohort documented a doubling of uterine perforation risk when insertion occurred within 36 weeks of cesarean birth (7). This indolent nature of migration directly led to a marked diagnostic delay, as the patient’s non-specific urinary symptoms were initially misleadingly attributed to common causes, a phenomenon frequently reported in the literature (12, 16–18). This case underscores a vital clinical imperative: in any woman with a long-term IUD, particularly with a prior cesarean section, new or persistent lower urinary tract symptoms must raise suspicion for IUD migration.

The pathogenesis of IUD-induced bladder stones is multifactorial. The displaced IUD initiates the process by serving as a nucleation scaffold for crystals, consistent with crystallization theories (19). Copper release then promotes mineralization via an inflammatory response, a recognized pathway in stone formation (20). The foreign body also facilitates urease-producing bacterial colonization, resulting in infection stones (21, 22). This comprehensive mechanism explains the inefficacy of empirical antibiotics and the persistence of symptoms (11, 23).

Furthermore, this case underscores the critical importance of precise preoperative imaging in preventing iatrogenic complications. Pelvic CT proved indispensable by clearly demonstrating complete uterine wall perforation by the IUD, with its intravesical segment encased within a rigid, hook-shaped calculus (Figures 1A–D). Attempted blind hysteroscopic retrieval based solely on ultrasound findings could have resulted in avulsion of this structure, potentially causing significant bladder laceration. This experience reinforces existing recommendations that for any missing IUD, confirming its extrauterine location and spatial relationships through cross-sectional imaging is essential for ensuring safe management (24, 25).

The definitive treatment strategy was guided by this detailed preoperative assessment. CT findings of a relatively small and adherent calculus permitted minimally invasive transurethral extraction under cystoscopic guidance without requiring lithotripsy. Management was further individualized based on the nature of the injury; given the full-thickness bladder wall perforation, prolonged postoperative urinary catheterization was implemented to promote spontaneous healing through continuous decompression, consistent with the principle of promoting healing by reducing tension on the wound (26). Although the cystoscopic defect was only 2 mm, we recognize that vesico-uterine fistulae can declare themselves months later; hence prolonged, structured follow-up was arranged. The successful outcome ultimately depended on seamless MDT collaboration between gynecology and urology services, spanning from joint preoperative planning to coordinated postoperative care.

This case provides several critical contributions to clinical practice, despite the inherent limitations of a single case report that may affect generalizability. It emphasizes the necessity of maintaining a high index of suspicion for IUD migration in at-risk patients, particularly those with a history of uterine surgery, as asymptomatic or atypical presentations can delay diagnosis (10, 27). Furthermore, it underscores the indispensable role of cross-sectional imaging, such as CT, in precise preoperative planning to avoid catastrophic complications during retrieval (28, 29). Finally, it exemplifies how a meticulously planned, MDT approach–integrating gynecology and urology–forms the cornerstone of managing this complex condition, thereby ensuring patient safety and successful clinical outcomes.