How effective is it?
Over 99 per cent effective. Less than one woman in 100 will get pregnant over five years.
How does it work?
A small plastic and copper device is put into the uterus. It stops sperm reaching an egg, and may also stop a fertilised egg implanting in the uterus.
What are the advantages?
- Works as soon as it is put in.
- Can stay in 5–10 years depending on type, but can be taken out at any time.
- You do not have to think about contraception for as long as the IUD is in place.
- When the IUD is removed your fertility will return to normal.
What are the disadvantages?
- Periods may be heavier or longer and more painful.
- Very small chance of getting an infection during the first 20 days after insertion.
- Insertion can be uncomfortable.
Anything else I should know?
- If fitted after 40 it can stay in place until the menopause.
- Women are taught to check the IUD is in place.
- A check for any existing infection is usually advised before an IUD is put in.
- Not affected by other medicines.