how effective is the copper iud

The copper IUD is highly effective, with an effectiveness rate of more than 99%. This means that out of 100 people using a copper IUD for a year, about one might become pregnant. It works immediately after insertion and can provide long-term contraception, lasting typically between 5 to 10 years depending on the device type. The copper IUD prevents pregnancy primarily by stopping sperm from fertilizing an egg and making it difficult for a fertilized egg to implant in the uterus. Additionally, it is also highly effective as emergency contraception if inserted within five days after unprotected sex, with a failure rate of about 0.1% in this context. Its effectiveness remains consistently high even over many years of use, with very low cumulative pregnancy rates reported over 12 years of use for devices like the Copper T-380A.