Complications caused by an IUS are rare and usually happen in the first six months after it has been fitted.
Pelvic infections
Pelvic infections may occur in the first 20 days after the IUS has been inserted.
The risk of infection from an IUS is extremely small (less than one in 100 in women who are at low risk of sexually transmitted infections (STIs). A GP or clinician will usually recommend an internal examination before fitting an IUS to be sure that there are no existing infections.
If you have any pain in your lower abdomen or have a high temperature or smelly discharge in the first three weeks after your IUS is fitted, see your GP or clinician immediately. This may be pelvic inflammatory disease (PID), which can lead to infertility.
Rejection
Occasionally, the IUS is rejected by the womb (expulsion) or it can move (displacement). This is not common and is more likely to happen soon after it has been fitted. Your doctor or nurse will teach you how to check that your IUS is in place.
Damage to the womb
In rare cases, an IUS can pierce the womb or neck of the womb (cervix) when it is put in. This can cause pain in the lower abdomen but doesn't usually cause any other symptoms. If the doctor or nurse fitting your IUS is experienced, the risk of perforation is extremely low.
If perforation occurs, you may need surgery to remove the device. Contact your GP straight away if you feel a lot of pain after having an IUS fitted. Perforations should be treated immediately.
Ectopic pregnancy
If the contraception fails and you become pregnant, your IUS should be removed as soon as possible if you are continuing with the pregnancy. There's a small increased risk of ectopic pregnancy if a woman becomes pregnant while using an IUS.
