An intrauterine device (IUD) is a small, T-shaped contraceptive placed inside the uterus, offering highly effective, long-term pregnancy prevention. Attached to the IUD are two thin, plastic strings that hang a few centimeters into the vaginal canal. These strings allow a healthcare provider to safely remove the device when replacement or removal is desired. Monthly self-checks are often recommended, as feeling the strings confirms the IUD is correctly positioned. The inability to locate these strings can cause concern, though up to 18% of IUD users experience this issue at some point.
Common Reasons Why Strings Are Missing
The most frequent reasons for not feeling the strings are benign and do not signify a problem with the IUD itself. A common explanation is that the strings have curled up and coiled into the endocervical canal, the passage connecting the vagina to the uterus. When this happens, the strings rest against the cervix and are out of reach.
The position of the cervix naturally changes throughout the menstrual cycle, which can affect string visibility. During ovulation, the cervix often moves higher, making the strings harder to reach. Checking again during your period, when the cervix is lower, may make the strings accessible.
Sometimes, the strings were cut intentionally short during insertion to prevent a partner from feeling them during intercourse. If they are too short, they may be correctly positioned but simply out of range. Changing your checking position, such as squatting instead of standing, can sometimes help shorten the distance to the cervix.
When Missing Strings Signal a Problem
Missing strings can occasionally indicate a serious issue with the IUD’s position. The most common complication is partial or complete expulsion, which occurs when the IUD slides out of the uterus, either partially into the cervix or completely out of the body. Expulsion most frequently occurs within the first year after insertion, often during a menstrual period, and results in a loss of contraceptive protection.
A less common concern is uterine perforation, where the IUD pushes into or through the wall of the uterus. This complication is rare, occurring in about 1 to 2 out of every 1,000 insertions, and usually happens during the insertion process itself. Perforation can lead to the IUD migrating outside the uterine cavity into the pelvic or abdominal area, a condition known as translocation.
Missing strings may also signal displacement, where the IUD has shifted slightly from its optimal position. A displaced IUD has reduced contraceptive effectiveness, increasing the risk of unintended pregnancy. These serious events may be accompanied by symptoms like severe cramping, heavy bleeding, or unusual discharge, which warrant immediate medical attention.
Immediate Steps to Take
If you cannot locate your IUD strings, assume your contraceptive protection may be compromised. You must begin using a reliable backup method of birth control, such as condoms or abstinence, until a healthcare provider confirms the IUD’s correct position. This precaution prevents unintended pregnancy, especially if the IUD has partially or fully expelled.
Until the IUD’s location is confirmed, avoid inserting anything into the vagina, including tampons or menstrual cups, to prevent disturbing a dislodged device. It is also recommended to take a home pregnancy test if you have recently had unprotected intercourse.
Contact your healthcare provider to schedule an appointment to determine the cause of the missing strings. If you are experiencing symptoms like fever, chills, severe pelvic pain, or abnormal vaginal bleeding, seek urgent care, as these could indicate a serious complication like infection or perforation.
Medical Procedures for String Localization
The initial step in locating the strings is typically a speculum examination. The provider uses a speculum to visualize the cervix and may use a specialized instrument, like a cytobrush, to gently sweep the endocervical canal. This often successfully uncoils the strings and brings them into view, allowing the provider to grasp them.
If the strings cannot be visualized or retrieved during the speculum exam, the next step is usually a transvaginal pelvic ultrasound. This imaging technique uses sound waves to create a clear picture of the uterus, confirming whether the IUD is present and correctly located within the uterine cavity.
If the ultrasound confirms the IUD is in place, but the strings are still not visible, the provider may use special forceps or a thin instrument called a thread retriever to attempt an in-office removal if the patient desires it.
If the ultrasound does not show the IUD in the uterus, it suggests that the device has been expelled or has migrated outside the uterine wall. In this scenario, an abdominal X-ray is often performed to determine if the IUD has moved into the pelvic or abdominal cavity, a sign of uterine perforation. Once the IUD’s location is confirmed, a plan is made for either removal—which may require a minor surgical procedure like hysteroscopy or laparoscopy if it has perforated—or for replacement if it was expelled.