Anticoncepción
IUDs (hormonal and copper)
Revisado: 4 de octubre de 2026
Solo en inglés por ahoraAn IUD, or coil, is a small T-shaped device placed in the womb that prevents pregnancy for years. Copper and hormonal IUDs work differently and affect periods differently.
What an IUD is
An intrauterine device (IUD), often called a coil, is a small T-shaped piece of plastic that a doctor or nurse places inside the womb (uterus). There are two main kinds. The copper IUD contains no hormones. It releases copper into the womb, which stops sperm from reaching an egg. The hormonal IUD, also called an IUS, releases the hormone progestogen. It works in more than one way. It mainly keeps sperm away from an egg, and in some people it also stops an egg being released or makes the womb less likely to accept one.
How well it works
Both types are over 99% effective. Because there is nothing to remember once it is in place, typical use is the same as perfect use: fewer than 1 in 100 people using an IUD get pregnant in a year. A copper IUD works as soon as it is fitted and lasts 5 or 10 years, depending on the type. A hormonal IUD also lasts for several years, depending on the type. A copper IUD can be used as emergency contraception too. Neither type protects against sexually transmitted infections (STIs).
Effects on your periods
The two types tend to change bleeding in different ways. With a copper IUD, periods may become heavier, longer or more painful, and you may bleed between periods. This may improve after a few months. A hormonal IUD tends to make bleeding lighter or irregular, and for some people periods stop. Logging your bleeding in Ciclo can help you see whether a new pattern is settling.
Fitting and removal
A doctor or nurse fits the IUD at an appointment. You may have period-like pain for a few days afterwards. When you want to stop using it, or when it needs replacing, a doctor or nurse can take it out. Once a copper IUD is removed, your fertility goes back to what it was before straight away.
Possible risks
Possible risks with a copper IUD include a pelvic infection, usually within 3 weeks of fitting, and the IUD moving or coming out, usually within 3 months. Other possible risks are damage to the womb and, in the rare case that the IUD fails, a pregnancy outside the womb (ectopic pregnancy). There is also a small chance of thrush that keeps coming back.
When to get help
Contact a doctor or nurse urgently if you have pain low in your tummy that painkillers do not help, or sudden tummy pain that gets worse or does not go away. Also get help quickly if you have a high temperature, abnormal or smelly discharge, very heavy bleeding, or you cannot feel the IUD threads or they feel different. Get emergency help if you have severe pain, especially on one side, and you think you could be pregnant.
This is general information. A doctor or nurse can help you decide whether an IUD suits you and which type is best for you.