It is very unlikely to get pregnant with an intrauterine device (IUD). Both hormonal and copper IUDs are over 99% effective at preventing pregnancy, meaning fewer than 1 in 100 women with an IUD will conceive while using it. The chance of pregnancy is less than 1% because IUDs either create an environment hostile to sperm and fertilization (copper IUD) or prevent sperm from reaching the egg and change the uterine lining (hormonal IUD).
However, certain conditions can reduce effectiveness:
- The IUD can fall out or be expelled unnoticed.
- The IUD can shift out of the proper position.
- Using the IUD beyond its recommended lifespan.
- Hormonal IUDs take up to a week to become effective after insertion.
- Pregnancy can technically occur during ovulation even with an IUD, though improbably.
In conclusion, pregnancy with an IUD is rare but possible, with an estimated effectiveness rate of about 99% or higher, making it one of the most reliable forms of birth control available.
