Effect of IUDs on an ongoing pregnancy

Levonorgestrel-releasing IUDs (LNG-IUDs) and copper IUDs are the only contraceptive methods that can adversely affect an ongoing pregnancy. Every effort must be made to exclude an early pregnancy at the time of insertion; see Starting intrauterine contraception.

An unintended pregnancy in someone with an IUD in place is more likely to be ectopic compared to conception if no contraception is used. Around 50% of pregnancies with an LNG-IUD in place, and up to 18% of those with a copper IUD in place, are ectopic.

If an unintended pregnancy occurs in someone with an IUD in place and gestation is less than 12 weeks, remove the IUD as soon as possible. If threads are not visible and the individual wishes to continue with pregnancy, refer for specialist removal under ultrasound guidance. If the IUD cannot be removed, there is a high risk of a second-trimester miscarriage or premature delivery. There is no increased risk of congenital abnormalities in pregnancies carried to term.

If pregnancy occurs in someone with an IUD in place and gestation is 12 weeks or more, refer to an obstetrician for management if the individual wishes to continue with the pregnancy. Alternatively, refer for a surgical abortion.