An intrauterine device (IUD) is a highly effective, long-acting reversible contraceptive method placed directly into the uterus. Once properly positioned, this small, T-shaped device provides continuous protection against pregnancy for several years. The IUD has thin threads, commonly referred to as strings, which extend out of the cervix. These strings allow a healthcare provider to easily remove the device and offer the user a method to routinely check that the IUD remains correctly in place. Understanding their normal position and function is a simple way to maintain confidence in the device’s effectiveness.
The Function and Initial Length of IUD Strings
The IUD strings are typically made of thin, flexible plastic or nylon material, often described as monofilament threads. These threads are attached to the base of the IUD and pass through the cervical canal into the top of the vagina. Their presence confirms the IUD is still inside the uterine cavity and has not been expelled.
During the insertion procedure, a healthcare provider trims the strings to a length appropriate for the patient’s anatomy. The standard length is generally cut so that the strings hang approximately 1 to 2 inches (about 2.5 to 5 centimeters) outside the opening of the cervix. This measurement is not meant to reach the vaginal opening, but rather to be easily located by a finger inside the upper part of the vagina.
The precise length is individualized. The provider aims to leave enough string for the user to reliably feel them without causing discomfort for the user or their partner. These thin threads often soften over time and naturally curl up around the cervix, which is the firm, rubbery entrance to the uterus. The goal is not to see the strings, but to simply confirm their presence by touch.
How to Perform a String Check
Regularly checking the IUD strings is a simple process that helps confirm proper placement, especially in the first few months after insertion. Before beginning the check, wash your hands thoroughly with soap and water to maintain hygiene and prevent the introduction of bacteria. The optimal time for a check is often after the end of your menstrual cycle, as the cervix naturally sits lower in the vagina during this phase.
To perform the check, get into a comfortable position, such as squatting or resting one leg on a raised surface. Carefully insert your index or middle finger high into the vagina until you can feel the cervix, which has a distinct firmness similar to the tip of your nose. Once the cervix is located, gently sweep your finger around the opening to feel for the fine, thread-like strings.
The strings should feel like one or two pieces of fishing line emerging from the center of the cervix. Note the sensation and the approximate length relative to the tip of your finger and the cervix, establishing a baseline for future checks. It is important to avoid pulling or tugging on the strings, as this action could inadvertently shift the IUD out of its correct position.
Interpreting Changes in String Length
A noticeable change in the perceived length or presence of the IUD strings is the primary indicator that the device may have moved. It is important to distinguish between a minor difference in sensation, which can be normal, and a significant physical change. The cervix itself moves slightly throughout the menstrual cycle, sitting lower during menstruation and higher during ovulation, which can temporarily make the strings feel shorter or longer without the IUD having shifted.
If the strings suddenly feel shorter than your established baseline or cannot be found at all, it may be due to a benign reason, such as the strings curling tightly into the cervical canal. However, a missing string can also be a sign of partial or complete IUD expulsion from the uterus. In rare cases, a missing string could indicate that the device has perforated the uterine wall.
Conversely, if the strings feel significantly longer than they did before, this is often the clearest indication of partial expulsion. This change means the IUD has moved downward and is descending through the cervix into the vagina, which compromises its effectiveness. If you feel the hard, plastic tip of the IUD itself protruding from the cervix, this is definitive proof that the device is displaced and no longer a reliable contraceptive.
Immediate Steps When String Position is Unsure
If you perform a string check and notice a significant change in length, or if you cannot feel the strings after having consistently found them before, you must take immediate action. First, begin using a non-IUD form of contraception, such as condoms, or abstain from intercourse until a medical professional has confirmed the IUD’s position. This step is necessary because any displacement can reduce the device’s ability to prevent pregnancy.
Resist the urge to manipulate the strings or try to push the IUD back into place yourself. Any attempt to adjust the device could cause further displacement or injury. Promptly schedule an appointment with your healthcare provider for an examination. They can use specialized instruments or an ultrasound to confirm the IUD’s exact location within the uterus.