IUDs are a highly effective, long-acting form of reversible contraception, offering over 99% efficacy in preventing pregnancy. The device is a small, T-shaped object placed inside the uterus. While IUDs are generally safe, displacement is a common concern. Although uncommon, typically occurring in 2–10% of users within the first year, shifting requires prompt attention to maintain contraceptive protection.
Understanding IUD Movement
An IUD is designed to sit securely in the upper part of the uterine cavity, but it can shift in two primary ways: expulsion or migration. Expulsion is the most frequent type of movement, where the IUD slides partially or entirely out of the uterus, through the cervix, and into the vagina. A partial expulsion means the device is no longer fully seated, while a complete expulsion means it has fallen out of the body.
The second type of movement is migration, which involves the device moving through the uterine wall, a process called perforation. Perforation is a rare complication, estimated to occur in about 1 to 2 per 1,000 insertions, and often happens during insertion. Once an IUD is outside the uterus, it can migrate into the pelvic or abdominal cavity, potentially causing injury to nearby organs like the bladder or intestines.
How to Recognize Displacement
The most practical way to check for IUD displacement is by performing a monthly string check, ideally after your menstrual period when the cervix is lower. After washing your hands, insert a finger into the vagina until you feel the firm cervix. You should be able to feel the thin, plastic strings extending from the cervix, which are typically cut to be about one to two inches long.
A change in the perceived length of the strings is a primary sign of movement. If the strings feel noticeably longer, the IUD may be partially expelled and moving downward. If the strings feel shorter than usual or are completely absent, the IUD may have shifted upward or been expelled without notice. Avoid pulling on the strings, as this could unintentionally dislodge the device.
Physical symptoms can also signal displacement. Common indicators include new or worsening abdominal pain and severe cramping beyond typical menstrual discomfort. Other signs are unexpected or heavy vaginal bleeding, or a sudden return to pre-IUD bleeding patterns. If you or your partner feel the hard, plastic body of the IUD during intercourse, or if you experience pain during sex, the device is likely dislodged.
Key Factors Increasing Movement Risk
Several physiological and situational factors can increase the likelihood of an IUD shifting out of place. One of the strongest predictors for expulsion is heavy or prolonged menstrual bleeding. Strong uterine contractions during menstruation are believed to physically push the device downward.
The timing of the IUD insertion relative to a pregnancy also plays a role in stability. Insertion immediately following a birth, such as within 48 hours of delivery, is associated with a higher risk of expulsion compared to a later insertion. Young age is another factor, with individuals under 25 years old showing a higher rate of expulsion.
Certain anatomical conditions can predispose a person to displacement. Structural irregularities of the uterus, such as the presence of fibroids or an unusually small uterine cavity, can prevent the IUD from seating properly. A patient who has previously experienced an IUD expulsion is also at a higher risk of having a subsequent device move out of position.
Consequences and Medical Management
The most significant consequence of IUD displacement is the potential for unintended pregnancy, as the device loses effectiveness when not properly positioned. Even a slight shift compromises function, requiring the immediate use of a backup contraceptive method if displacement is suspected. In rare cases of perforation, the IUD moving outside the uterus can lead to complications like infection or internal injury, sometimes requiring surgical intervention.
If you suspect your IUD has moved, contact a healthcare provider promptly. Avoid attempting to adjust or remove the device yourself, as this can cause injury or worsen the displacement. Your provider will perform a pelvic examination to check the strings and may follow up with a transvaginal ultrasound to confirm the IUD’s exact location.
If the IUD is partially expelled, it must be removed, and a new device may be inserted during the same visit. If the IUD cannot be located in the uterus via ultrasound, an X-ray or other imaging is used to determine if it has perforated and migrated into the abdominal cavity. A migrated device generally requires surgical removal, most commonly through laparoscopy.