How to Choose the Right IUD

Evaluating Size, Duration, and Method of Action

Intrauterine devices (IUDs) are T-shaped devices that can be inserted into your uterus to prevent pregnancy. There are five brands of IUDs approved by the U.S. Food and Drug Administration (FDA) and available for use in the United States:

  • Kyleena
  • Liletta
  • Mirena
  • Paragard
  • Skyla

While IUDs are considered among the most effective birth control options, there are differences between the brands that you should consider. Knowing more about them can help you decide whether an IUD is right for you and, if so, which one.

how to choose an IUD
Illustration by Brianna Gilmartin, Verywell

Similarities Between IUD Brands

IUDs all have a number of similarities.

From the broadest perspective, all of the IUDs approved by the FDA are considered to be highly effective methods of birth control.

They can be used on their own and are reversible, meaning that you can become pregnant once you stopping using the IUD.

All IUDs must be placed into your uterus and removed by a healthcare provider. Depending on the brand, they can be kept in place for anywhere from three to 10 years.

IUDs generally have a low risk of side effects and adverse events. However, they can fall out, in which case you can get pregnant until you begin to use another method of birth control or have your IUD replaced.

There is also a slight risk of pelvic infection or a uterine perforation, although these complications are uncommon.

Medical evidence indicates that due to an IUD being in the uterus, there is a slightly increased risk of an ectopic (tubal) pregnancy, which is a non-viable and potentially life-threatening pregnancy that implants in the fallopian tube. Ectopic pregnancies can cause the tube to rupture, which can cause significant bleeding.

Differences Between IUD Brands

The main distinction among the different IUDs is that all but one release the hormone levonorgestrel (a progestin) to prevent pregnancy. ParaGard, which is hormone-free, works because it is made of copper.

Hormonal IUDs

Marketed under the brand names Mirena, Liletta, Skyla, and Kyleena, these IUDs are made of a polydimethylsiloxane sleeve that contains levonorgestrel on the stem.

Levonorgestrel prevents pregnancy by thickening cervical mucus, thinning the uterine wall, and impairing sperm's ability to bind to an egg. Not only is fertilization unlikely, the odds of implantation are low even if fertilization occurs.

The hormone doses differ for each of the levonorgestrel IUDs. They each initially release a higher dose of the hormone, which decreases over time. Even as the released dosage declines, the device remains effective in preventing pregnancy throughout the duration of recommended use and so long as it remains in its proper position.

Each brand is recommended for a specified time period, ranging from three to seven years.

Brand Initial Dose Maximum Length of Use
Skyla 14 mcg 3 years
Liletta 19.5 mcg 8 years
Kyleena 17.5 mcg 5 years
Mirena 20 mcg 7 years

Because these four IUDs contain progestin, you may experience a decrease in your menstrual flow. For instance, you may spot for the first few months and then have lighter and shorter periods. Your period may also stop altogether, which is considered safe.

Other side effects may include:

  • Headaches
  • Nausea
  • Breast tenderness
  • Depression
  • Decreased libido
  • Hair loss
  • Ovarian cysts

Copper IUD

Paragard is the only hormone-free IUD approved by the FDA. It is composed of polyethylene wrapped with copper wire and works entirely differently to prevent pregnancy.

Paragard triggers an inflammatory response to the copper, which damages the egg, impairs sperm's movement and ability to live, and diminishes the ability of an egg to implant even if it is fertilized.

Of all the IUDs, the Paragard can be used for the longest duration, which is up to 10 years.

Because the copper IUD is hormone-free, it should not alter the timing of your menstrual cycle. However, it may cause heavy periods with more cramping or back pain than usual, especially in the first several menstrual cycles after its placement.


You should consider several factors when selecting an IUD. Have an open discussion with your healthcare provider about them before making a decision.

If you've had repeated episodes of pelvic inflammatory disease, liver disease, or irregular menstrual bleeding, an IUD may not be right for you. You and your healthcare provider can discuss the risks and benefits of an IUD in your specific case.

Hormone Exposure

The hormone in Liletta, Kyleena, Mirena, and Skyla is only released into the uterus, so it does not have the same kind of broad effect as the hormones found in birth control pills.

Remember, though, that the hormone dose released by each device differs, which may be a particularly important consideration if you experience related side effects and menstrual changes.

If you've had adverse effects from hormone exposure or have a history of breast, cervical, uterine, or ovarian cancer, you may choose to stay away from hormone use altogether. The Paragard IUD may be the best choice for you.

Duration of Effectiveness

As mentioned, the length of time you can keep the device in place ranges fairly substantially.

When factoring this into your decision making, also consider:

  • Your finances: Earlier removal/replacement means more medical appointments and device charges over time.
  • Your schedule: It's more convenient to have a longer-lasting IUD.
  • Your plans for conception: While you can have an IUD taken out at any time if you would like to try to get pregnant, a device with a longer lifespan may not be necessary if you think you may start trying in a few years.

Size of the IUD

Skyla and Kyleena are a little bit smaller than Mirena, Liletta, and Paragard. Because of this, Skyla and Kyleena may be better tolerated by those who have a smaller uterus, including teenagers and perimenopausal people.

Who Should Not Use an IUD

You should not use any IUD if you:

  • Are pregnant or suspect you are
  • Have unexplained vaginal bleeding
  • Have an ongoing pelvic infection
  • Have known or suspected uterine or cervical cancer
  • Have any uterine abnormality that interferes with the placement of the IUD (e.g., fibroids)

A Word From Verywell

No matter which IUD you choose, you can have the peace of mind that all five are considered safe and among the most effective forms of birth control methods.

In fact, they are as effective as permanent methods, like vasectomies and tubal ligation. Additionally, they do not affect your chance of getting pregnant after removal. 

It's important to remember that IUDs do not protect you from sexually transmitted infections (STIs). You need to use a barrier method of protection if you are sexually active with a partner who could be living with an STI.

Frequently Asked Questions

  • What is levonorgestrel?

    Levonorgestrel is a progestin, a synthetic version of the hormone progesterone. Levonorgestrel is used to prevent pregnancy and is found in Skyla, Liletta, Kyleena, and Mirena IUDs. 

  • Will a hormonal IUD cause weight gain?

    It shouldn't. Hormonal IUDs use a synthetic version of progesterone, which does not cause weight gain. Some women may experience stronger hunger signals when using progesterone, which if you aren't careful can cause weight gain.

    Progesterone may actually help you lose weight. If you have low progesterone levels, a hormonal IUD can help balance your hormones and improve your metabolism. In addition, progestin has diuretic properties, which can help you to shed water weight.

  • Which IUD has the most progesterone?

    Mirena. Mirena has more progesterone than Kyleena and can be left in place longer. Mirena lasts for seven years and contains 20mcg of levonorgestrel. Kyleena has 17.5 mcg and can be left in place for 5 years. Liletta has 19.5 mcg, but only lasts eight years. Skyla has the lowest dose of progesterone at 14 mcg. It is only good for three years. 

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Yoost J. Understanding benefits and addressing misperceptions and barriers to intrauterine device access among populations in the United States. Patient Prefer Adherence. 2014;8:947–957. doi:10.2147/PPA.S45710

  2. Nelson AL, Massoudi N. New developments in intrauterine device use: focus on the US. Open Access J Contracept. 2016;7:127–141. doi:10.2147/OAJC.S85755

  3. Grandi G, Farulla A, Sileo FG, Facchinetti F. Levonorgestrel-releasing intra-uterine systems as female contraceptives. Expert Opin Pharmacother. 2018;19(7):677-686. doi:10.1080/14656566.2018.1462337

  4. Sanders JN, Adkins DE, Kaur S, Storck K, Gawron LM, Turok DK. Bleeding, cramping, and satisfaction among new copper IUD users: a prospective study. PLoS One. 2018;13(11):e0199724. doi:10.1371/journal.pone.0199724

Additional Reading

By Dawn Stacey, PhD, LMHC
Dawn Stacey, PhD, LMHC, is a published author, college professor, and mental health consultant with over 15 years of counseling experience.