An intrauterine device (IUD) is a small, T-shaped piece of flexible material inserted into the uterus. Functioning as a long-acting reversible contraceptive, this method of birth control is highly effective, preventing pregnancy with an efficacy rate over 99%. IUDs are designed to remain securely in place for several years, depending on the type. Although the risk of significant movement is low, understanding how and why displacement might occur is important for users concerned about the device shifting position within the body.
How IUDs Can Shift or Displace
IUD movement is categorized into three types of displacement, each affecting contraceptive protection differently. The most common form is partial expulsion, where the device moves downward from its optimal position in the upper uterus (the fundus). The IUD may become lodged in the lower uterine segment or the cervix. This placement reduces contraceptive effectiveness and may cause discomfort.
A complete expulsion occurs when uterine muscles contract and push the IUD entirely out of the uterus, through the cervix, and into the vaginal canal. This process often happens during menstruation, when the uterus naturally contracts to shed its lining. An unnoticed complete expulsion results in an immediate loss of contraception. The expulsion rate is typically highest within the first year after insertion, often occurring within the first few months.
The third and most serious type of movement is perforation or migration, an extremely rare complication. Perforation involves the IUD puncturing the uterine wall, either partially or completely, often during the insertion procedure. If the device passes through the uterine wall, it can migrate into the pelvic or abdominal cavity, potentially interacting with surrounding organs. This complication is estimated to occur in approximately one to two out of every 1,000 insertions.
Factors That Increase Displacement Risk
The physical anatomy of the uterus plays a significant part in the risk of IUD displacement. If the IUD is not appropriately sized for the user’s uterine cavity, it can cause the uterus to generate contractions in an attempt to expel the foreign body. Structural irregularities in the uterus, such as the presence of fibroids or a naturally smaller uterine size, can also increase the likelihood that the device will be pushed out of its correct position.
The timing of IUD insertion also affects the risk of movement. Inserting the device immediately postpartum, soon after giving birth, is associated with a higher rate of expulsion. This increased risk occurs because the uterus needs time to return to its pre-pregnancy size and shape.
Certain physiological conditions also contribute to device displacement. Individuals who experience heavy menstrual bleeding (menorrhagia) have a significantly increased risk of IUD expulsion. The strong, frequent uterine cramps associated with heavy flows are believed to physically push the device downward. Younger individuals, particularly those aged 24 and under, may also have a higher rate of expulsion, possibly linked to a smaller uterine cavity size.
Recognizing the Symptoms of Movement
A common way users notice a possible shift is through changes in the palpable strings. The strings, which hang a short distance into the vagina, may suddenly feel shorter or longer than they did previously. If the strings cannot be felt at all, the IUD may have moved higher into the uterus or been expelled entirely without being noticed.
Another sign of movement is the onset of new or worsening pain and cramping. While some cramping is normal immediately following insertion, a displaced IUD can cause sharp, sudden, or persistent lower abdominal pain. This pain is often not relieved by typical medication and results from the uterus contracting against the displaced device.
A change in bleeding patterns may also signal that the IUD is no longer positioned correctly. Users of hormonal IUDs, who often experience lighter periods or no period at all, might notice a sudden return of heavy or irregular vaginal bleeding. For those with a copper IUD, a shift in position might lead to an abnormal change in their typically heavier menstrual flow. Additional indicators that the device has moved include pain during sexual intercourse or a partner feeling the hard plastic tip of the IUD in the vaginal canal.
Next Steps If You Suspect Displacement
If any symptoms of IUD movement are noticed, the immediate action is to use a backup method of contraception, such as condoms. A displaced IUD cannot guarantee protection against pregnancy, and a misplaced device can carry complications if pregnancy occurs.
The next step is to contact a healthcare provider to schedule an examination as soon as possible. Avoid attempting to adjust or reinsert the IUD yourself, as this can cause further injury or displacement. A healthcare professional will perform a physical exam and may use an ultrasound to confirm the exact position of the IUD within the uterus.
If the IUD is confirmed to be displaced, the provider will discuss the appropriate course of action, which typically involves removal of the current device. In many cases, a new IUD can be inserted immediately during the same appointment, or the user may choose to switch to a different method of contraception. If the IUD has migrated through the uterine wall, surgical intervention may be required for safe removal.