Intrauterine devices (IUDs) are highly effective for contraception, but they can sometimes shift from their intended position. While rare, understanding this possibility helps users stay informed. Recognizing signs of displacement and knowing what to do ensures continued effectiveness and peace of mind.
How IUDs Are Designed to Stay in Place
IUDs are designed with a T-shape to fit snugly within the uterine cavity. Once inserted, the flexible arms extend, stabilizing the device high in the uterus, near the fallopian tubes. This placement aims for maximal contraceptive effectiveness. The uterus is a muscular organ with a small, triangular cavity that naturally cradles the IUD, further contributing to its stability.
The uterine walls contribute to holding the IUD in place through their natural contractions and overall shape. The IUD’s design allows it to withstand these forces in most cases. This snug fit makes it uncommon for an IUD to be dislodged during daily activities, including exercise or sexual intercourse.
Factors That Can Cause IUD Movement
Despite their design, IUDs can sometimes shift from their optimal position due to various factors. Partial or complete expulsion, where uterine contractions push the IUD partially or entirely out of the uterus and into the vagina, is one such factor. Complete expulsion occurs in about 5-10% of women during the first year, most often in the initial months after insertion, and is more common if the uterine cavity is too small for the device.
Uterine perforation, where the IUD embeds in or passes through the uterine wall, is a rare but serious complication. This risk is low overall, with a cumulative incidence of approximately 0.21% at one year and 0.61% at five years. Perforation risk is elevated if the IUD is inserted within one year postpartum, particularly between 4 days and 6 weeks after delivery, and in breastfeeding individuals.
Improper insertion by an inexperienced healthcare provider can also lead to malposition, where the IUD is in the uterus but not correctly seated in the fundus. Changes in uterine size or shape, such as those caused by fibroids or a uterus that has not fully returned to its pre-pregnancy size, can also increase the likelihood of displacement. While less common, vigorous activity or sexual intercourse might contribute to displacement if the IUD was not initially placed correctly or if it is early in the first few months after insertion.
Recognizing Signs of IUD Displacement
Recognizing the signs of IUD displacement is important for timely intervention. The most direct way to check is by regularly feeling for the IUD strings, which typically extend 1-2 inches into the upper vagina. If these strings feel noticeably shorter, longer, or are completely missing, it could indicate that the IUD has shifted. Avoid pulling on the strings when checking, as this could inadvertently dislodge the device further.
Beyond changes in string length, other symptoms may suggest IUD movement:
Increased or persistent pain and cramping, especially if severe or not relieved by over-the-counter medication.
Abnormal bleeding patterns, such as heavier or prolonged bleeding, or spotting between periods.
Feeling the IUD itself during sexual intercourse (should not happen if correctly positioned).
Unexpected pregnancy (in rare cases, as effectiveness is compromised).
What to Do if You Suspect Movement and Its Implications
If you suspect your IUD has moved, contact a healthcare provider immediately. Do not attempt to adjust or remove the IUD yourself, as this could cause further injury or displacement. While awaiting your appointment, use a backup form of contraception, such as condoms, as the IUD may no longer be effective in preventing pregnancy. Also avoid intercourse or tampon use until a healthcare professional has confirmed the IUD’s position.
The implications of a displaced IUD primarily involve reduced contraceptive effectiveness, increasing the risk of unintended pregnancy. If pregnancy occurs with an IUD in place, there is a higher chance of an ectopic pregnancy, where the fertilized egg implants outside the uterus. Additionally, a displaced IUD can lead to health risks such as increased pain, abnormal bleeding, and in cases of perforation, potential damage to the uterine wall or surrounding organs. A healthcare provider will typically perform a pelvic exam, and potentially an ultrasound or X-ray, to confirm the IUD’s location, after which they can professionally remove or reposition the device.