An intrauterine device (IUD) is a small, T-shaped contraceptive device placed into the uterus to prevent pregnancy. IUDs are highly effective, with an efficacy rate over 99%. A common concern is whether sexual activity could dislodge the device, causing it to shift out of place or be expelled. Understanding the anatomy and the actual causes of displacement can help alleviate this worry and provide confidence in this long-acting contraceptive option.
The Direct Answer: Why Sexual Activity Does Not Cause Displacement
The short answer is that sexual activity does not typically cause an IUD to be knocked out of place. The IUD sits securely inside the uterine cavity, which is located far above the vaginal canal where intercourse occurs. The vaginal canal is separated from the uterus by the cervix, a thick, muscular barrier that has only a small opening.
The IUD is positioned high up in the fundus of the uterus. During penetrative sex, the penis or other object enters the vagina but cannot physically reach the IUD itself. Only two thin strings extend beyond the cervix into the top of the vagina; these are not structural components. These strings are far too delicate to transmit the force needed to move the IUD from its secure position in the uterus.
Actual Risk Factors for IUD Expulsion
While sex is not a factor, IUD displacement (expulsion) is an uncommon risk where the device partially or fully shifts from its correct position. Expulsion happens spontaneously due to internal biological factors, not external forces. The most significant factor is the body’s natural tendency to contract the uterine muscle, particularly during menstruation. Strong uterine contractions, often experienced as cramping, can push the IUD downward.
Heavy menstrual bleeding is a strong indicator of a higher expulsion risk. Other physiological factors also play a role, including being 24 years old or younger. Individuals who have never given birth may also face a slightly elevated risk, possibly due to a smaller uterine cavity. The risk of the device moving is highest in the first three months after insertion, and it decreases significantly over time.
How to Monitor IUD Placement and Signs of Displacement
Monitoring IUD placement involves routinely checking the position of the strings that hang from the cervix. Providers recommend performing this self-check once a month, often after a menstrual period. To check the strings, wash your hands and insert a finger into the vagina until you feel the firm, rubbery cervix, which feels similar to the tip of your nose.
You should be able to feel the thin strings protruding from the cervix. If the strings feel longer or shorter than they did the previous month, the IUD may have shifted. Signs of displacement include being unable to feel the strings at all, which suggests the IUD has moved higher up or been expelled. Displacement is also indicated if you or your partner can feel the hard plastic of the IUD poking through the cervix.
If you suspect your IUD has moved, or if you experience severe cramping, abnormal bleeding, or pain during intercourse, contact your healthcare provider immediately. It is recommended to use a backup method of contraception until a medical professional confirms the IUD is correctly positioned. Do not attempt to push the IUD back into place or pull on the strings, as this could cause further issues.