An intrauterine device (IUD) is a highly effective, long-acting form of reversible contraception placed inside the uterus. Two thin plastic strings are attached to the IUD, extending through the cervix into the vagina. These strings allow the user to perform a monthly self-check to confirm the device is in place and permit a healthcare provider to easily remove the IUD. While discovering the absence of these strings can cause anxiety, it is common, with up to 18% of users reporting they cannot feel them at some point. The inability to feel the strings requires prompt attention to confirm the IUD’s position and continued contraceptive effectiveness.
Correct Technique for Checking IUD Strings
A systematic self-check is the first step in addressing the concern of missing strings, as they may be present but simply difficult to find. Begin by thoroughly washing your hands to prevent the introduction of bacteria. Assume a comfortable position, such as squatting or sitting on the edge of a toilet, which helps shorten the vaginal canal and makes the cervix more accessible.
Gently insert your index or middle finger into your vagina until you locate the cervix, which feels firm and rubbery, similar to the tip of your nose. The IUD strings should emerge from the cervical opening, feeling like fine, soft fishing line or taut dental floss. Perform this check around the same time each month, ideally after your menstrual period, because the cervix naturally sits lower then.
The length of the strings can fluctuate slightly throughout the menstrual cycle due to changes in cervical position, so a slight variation in feel is normal. If you feel the strings, note their length and texture for future comparison. If you feel the hard plastic of the IUD itself, or if the strings feel significantly longer or shorter than before, the device may have shifted. Contact your provider immediately if this occurs.
Why the Strings Might Be Absent
There are several reasons why the IUD strings may no longer be palpable during a self-check, with the most frequent being benign. The strings can simply curl up and retract into the endocervical canal, the passage between the cervix and the uterus. This often happens because the plastic material softens over time, causing the threads to coil against the cervix.
In some cases, the strings may have been trimmed too short during the initial insertion procedure. If the strings are cut very close to the cervix, they may be out of reach even when using the correct checking technique.
Another possibility is that the IUD has partially or completely moved out of the uterus, a process known as expulsion. This usually occurs in the first year of use. Any movement out of the proper location compromises its contraceptive effect.
A rare cause for missing strings is uterine perforation, where the IUD has moved through the wall of the uterus and potentially into the abdominal cavity. This complication is estimated to occur in only about one to one-and-a-half out of every 1,000 insertions. Perforation is more common in individuals who have recently given birth or are breastfeeding at the time of insertion.
Immediate Steps After String Loss
If you cannot feel your IUD strings, immediately begin using a backup method of contraception, such as condoms. The absence of strings means the device’s position cannot be verified, and its effectiveness may be compromised by a partial expulsion. Continue using barrier contraception until a healthcare provider confirms the IUD is correctly positioned.
Resist the urge to try and locate the device yourself by probing or pulling on anything you might feel, which could cause the IUD to shift further or cause injury. Immediately contact your healthcare provider or gynecologist to schedule an urgent appointment to investigate the missing strings. Make a note of any accompanying symptoms, as these can offer clues about the cause of the string loss.
Watch for the following symptoms, which could indicate an infection or complication like device expulsion:
- Severe or persistent cramping.
- Unusual vaginal discharge or odor.
- Unexpected heavy or irregular bleeding.
- Fever or chills.
If you had a hormone-releasing IUD and your typically light periods suddenly return to their original, heavier flow, this may also suggest the IUD has moved.
Medical Procedures to Locate the IUD
When you visit the clinic, the initial diagnostic step is usually a speculum examination to visualize the cervix. The provider will look for the strings and may use a specialized tool, such as a cytobrush, to gently sweep the endocervical canal. This procedure is often successful in retrieving strings that have simply coiled up into the canal.
If the strings are not located, the next step is typically a transvaginal ultrasound. This is the primary method for confirming the IUD’s location within the uterus. The ultrasound determines if the device is correctly positioned, partially expelled, or embedded in the uterine wall.
If the ultrasound confirms correct placement and you wish to keep the IUD, no further action is usually necessary. The provider may recommend using a different method of checking for placement moving forward.
If the ultrasound does not show the IUD inside the uterus, an abdominal X-ray is often ordered to check for uterine perforation. The X-ray confirms whether the device has migrated outside the uterus into the pelvic or abdominal cavity. If the IUD is misplaced or cannot be retrieved in the office, removal may require a hysteroscopy or, in the case of perforation, a laparoscopic surgical procedure.