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Types of IUD & How They Work

In this post, we’re going to take a look at specific kinds of birth control called IUDs. We’ll answer the question ‘what are IUDs?, explain the different types of IUD, as well as how they work, plus we’ll also cover IUD effectiveness and some side effects of using this contraceptive method too.

What are IUDs?

IUD stands for intrauterine device. The IUD, also known as the coil, can come in two different types, but both of these are long-acting birth control methods that are inserted into the uterus through the vagina.

Types of IUD

There are two types of IUD available, these are the copper IUD and the hormonal IUD. Now let’s dive a little deeper and break down how these different types of IUD work. 

How does the copper IUD work?

The copper IUD, or copper coil, doesn’t contain any hormones. Instead, this birth control method contains copper, which thickens cervical mucus, making it harder for sperm to swim through the female reproductive system. The copper also helps create a hostile environment in the uterus, preventing the implantation of a fertilized egg cell to the uterine wall.

Copper IUDs are long-acting. This means that they’re a non-hormonal birth control method that can be relied on for a number of years. Typically, copper IUDs work for between five to ten years. They require a healthcare professional to be fitted and removed. If fitted up to five days after unprotected sex, the copper IUD can also be used as an emergency birth control method.  

How does the hormonal IUD work? 

The hormonal IUD contains a synthetic version of the sex hormone progesterone. Like copper IUDs, the hormonal version also thickens cervical mucus, making it harder for sperm to reach the egg. The hormonal IUD can also stop ovulation (the release of an egg cell) from happening altogether.

Another long-term option, the hormonal IUD is fitted by a healthcare professional. Depending on the brand, the hormonal IUD can be used to prevent pregnancy for several years before it should be removed or replaced. 

IUD effectiveness

The IUD is considered a highly effective form of birth control. In fact, both the copper and hormonal IUD are more than 99% effective at preventing pregnancy. The IUDs’ high birth control effectiveness is partly down to the fact that, once it’s fitted, it requires practically no work from the individual. The high effectiveness of the IUD, combined with its low maintenance, makes it the choice of birth control for many women.  

IUD side effects

As with other hormonal or invasive birth control options, there are a number of side effects that women may experience when using IUDs to prevent pregnancy. These birth control side effects include:

Finding the right kind of birth control method for you

Birth control choice is a very individual thing. There are so many factors to consider, from effectiveness, to side effects, to family planning and lifestyle choice. The most important thing is that women have access to a multitude of birth control options and get hold of all the information they need in order to make informed decisions about their own reproductive health. 

The world’s first birth control app

Cleared by the FDA in 2018, Natural Cycles is 100% hormone-free. It’s the first birth control method of its kind, combining basal body temperature tracking with an algorithm that learns and predicts your own unique cycle. Thinking about going hormone-free? Find out if Natural Cycles could work for you today.

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Written By

Jennifer Gray

Jennifer Gray is an award-winning writer with more than five years’ experience covering reproductive topics ranging from birth control to planning pregnancy. She is passionate about providing women with accurate information grounded in science they can use to take charge of their own health - while also dispelling myths that exist within the field of women’s health. She holds a Master of Science from the University of Edinburgh and currently lives in Ireland.

Jack in a suit and tie holding a microphone and giving a presentation.

Scientifically Reviewed

Jack Pearson

Dr. Jack Pearson is a previously HCPC registered Embryologist with a PhD in reproductive medicine. Prior to joining Natural Cycles leading Medical Affairs, he worked for more than 10 years in a clinical setting working at some of the busiest fertility clinics in the UK. Today he spends most of his time working with experts at the world’s leading institutions to carry out important research with the vision to further the field of female health. He earned his PhD from the University of Sheffield specializing in Sperm Metabolism and currently lives in London.

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