How effective is the IUD?

Bottom lineIUDs are over 99% effective, among the most reliable contraceptives, because there's nothing to remember so typical and perfect use are nearly identical; hormonal IUDs release progestin and last 3 to 8 years (often lightening periods), while copper IUDs are hormone-free and last up to 10 years (and can be emergency contraception within 5 days). Both are reversible with quick return of fertility but offer no STI protection.

IUDs are among the most effective forms of contraception, over 99% effective, because once placed there's nothing to remember or get wrong.

The two types

• Hormonal IUD: releases progestin locally; effective for 3 to 8 years depending on the brand
• Copper IUD: hormone-free, works by making the uterus hostile to sperm; effective for up to 10 years

Why so effective

Unlike pills, IUDs aren't subject to user error - no daily action means typical use and perfect use effectiveness are nearly identical (both over 99%). That's why IUDs and implants are called "LARCs" (long-acting reversible contraceptives).

Other benefits

• Hormonal IUD: often makes periods lighter and can ease cramps; some people stop bleeding altogether
• Copper IUD: no hormones, can be used as emergency contraception if fitted within 5 days
• Reversible: fertility returns quickly after removal

Things to know

• Insertion can be uncomfortable and may cause cramping for a few days
• Copper IUDs can make periods heavier, especially at first
• Hormonal IUDs can cause irregular spotting initially
• No STI protection - use condoms for that

When to see a doctor

For fitting, removal, or if you have severe pain, fever, or can't feel the threads.

See hormonal vs copper IUD.

Femora helps you track bleeding changes after getting an IUD.