How Effective Is an IUD for Pregnancy, PMS, and More? (2025)

Intrauterine devices (IUDs) are one of the most effective and low-maintenance forms of birth control available, with a failure rate of less than 1% per year. They prevent pregnancy by either releasing hormones that prevent ovulation (hormonal IUD) or creating an environment that's hostile to sperm (copper IUD).

For some users, the benefits of IUDs may go beyond birth control. Hormonal IUDs can help reduce common menstrual problems like heavy menstrual bleeding and cramps. They may also offer relief for other conditions, like endometriosis and polycystic ovary syndrome (PCOS).

How Effective Is an IUD for Pregnancy, PMS, and More? (1)

IUDs and Pregnancy

IUDs are over 99% effective at preventing pregnancy. The low failure rates make IUDs a popular choice among those seeking long-acting reversible contraception (LARC). In the United States, 14% of all contraceptive users between 15 and 44 years old have an IUD.

Once a healthcare provider inserts the T-shaped device into the uterus, it works continuously for three to 10 years, depending on the type. This low-maintenance reliability makes IUDs a top choice for those looking for a reliable, long-term option that doesn't require daily upkeep like birth control pills. IUDs also eliminate the risk of user error with barrier methods like condoms or diaphragms.

In addition to preventing pregnancy, copper IUDs (Paragard) and two hormonal IUDs (Mirena, Liletta) can double as emergency contraception. If inserted within five days after having unprotected sex, these IUDs can prevent pregnancy with an effectiveness of over 99%, making them one of the most reliable postcoital options available.

IUD Effectiveness Comparison

While both hormonal and copper IUDs are highly effective, there are some slight differences in their function, effectiveness, and how long they last.

There are five intrauterine devices (IUDs) available in the United States. All five IUDs are over 99% effective at preventing pregnancy. The slight variations in failure rates are minimal, and choosing the most suitable IUD depends on how long you want the device to last, whether you hope to gain other benefits from IUD use (e.g., lighter periods), and personal preferences.

IUD Comparison: Effectiveness
IUD BrandTypeDuration of EffectivenessFailure Rate
ParagardCopperUp to 10 years0.8%
MirenaHormonalUp to 8 years0.2%
KyleenaHormonalUp to 5 years0.16%
LilettaHormonalUp to 8 years0.15%
SkylaHormonalUp to 3 years0.41%

Can IUDs Help Manage Certain Conditions?

Beyond contraception, IUDs—particularly hormonal types—offer therapeutic benefits for various reproductive health conditions. By releasing small amounts of progestin, hormonal IUDs may relieve symptoms of several conditions.

Endometriosis

Hormonal IUDs can reduce inflammation and endometriosis-associated abdominal and pelvic pain by thinning the uterine lining. A small study investigated how effective a hormonal IUD (levonorgestrel-releasing intrauterine system) is at reducing pain in women with endometriosis and improving their quality of life. It also examined changes in a blood marker (CA 125) linked to endometriosis severity.

The study found the hormonal IUD significantly decreased menstrual cramps (dysmenorrhea) and pain during intercourse (dyspareunia). Additionally, the size of endometriomas (blood-filled ovarian cysts associated with endometriosis) decreased in some women, and CA 125 levels (inflammation marker in the blood) also dropped.

Heavy Menstrual Bleeding (HMB)

By releasing a steady dose of progestin, hormonal IUDs thin the uterine lining, leading to lighter periods. For some, periods may become so light that they stop altogether, making hormonal IUDs a popular choice for people with heavy menstrual bleeding (HMB).

A study of 105 participants examined the effectiveness of a levonorgestrel-releasing 52-mg IUD in reducing heavy menstrual bleeding.

At the start, menstrual blood loss in study participants ranged from 73 to 520 milliliters (mL). After six months of IUD use, median blood loss had decreased by more than 90%. The results were consistent among all participants, regardless of body weight or childbirth history. While a few experienced side effects, the IUD proved to be a highly effective solution for managing heavy periods.

Polycystic Ovary Syndrome (PCOS)

​​While IUDs don't directly treat polycystic ovary syndrome (PCOS), hormonal IUDs can help manage symptoms like irregular bleeding. PCOS often causes irregular menstrual cycles and spotting (breakthrough bleeding) between periods due to hormonal imbalances.

When the uterine lining isn't shed regularly during a period, it can thicken over time, increasing the risk of endometrial hyperplasia, a condition in which the lining grows excessively. If left unchecked, hyperplasia can lead to more severe complications, including an elevated risk of endometrial cancer.

The progestin in hormonal IUDs counteracts this by thinning the uterine lining, reducing PCOS symptoms like irregular spotting and unpredictable periods. Hormonal IUDs can also make periods lighter or eliminate them, helping ease some symptoms of PCOS.

Premenstrual Syndrome (PMS)

Premenstrual syndrome (PMS) and its more severe form, premenstrual dysphoric disorder (PMDD), are driven by the body's sensitivity to the cyclical hormonal changes of the menstrual cycle. Symptoms can range from mild discomforts like bloating and irritability to severe mood swings, depression, and anxiety.

The effects of hormonal IUDs on people with PMS or PMDD remain unclear due to limited research. Studies have not explicitly focused on people with PMS or PMDD, making it difficult to determine whether hormonal IUDs can help or worsen PMS and PMDD symptoms.

Some women report mood changes with hormonal IUDs, including depressed mood or nervousness, especially during the first six months of use. Still, these side effects appear to be rare, with depression rates as low as 0.2–0.5% in more extensive studies. More research is needed to determine what effects they may have.

What Causes a Failure?

While IUDs have a failure rate of less than 1% per year, certain factors can reduce their reliability and cause them to fail. Possible causes of IUD failure include:

  • Expulsion: Sometimes, the IUD can fall out of place and partially or completely fall out of the uterus. Though rare, expulsion typically happens within the first three months following IUD placement. It is more common in people with overweight or obesity, those who have an IUD placed immediately following childbirth, and younger IUD users (24 and under).
  • Improper placement: An IUD can fail if it is not inserted correctly inside the uterus. Most healthcare providers require a follow-up appointment a few weeks after IUD installation to ensure proper placement.
  • Sexual intercourse before IUD is effective: Some IUDs can take up to seven days after placement to effectively prevent pregnancy. Having unprotected sex before the IUD begins working can result in pregnancy.
  • Device expiry: Using the IUD beyond its expiration date can reduce effectiveness and increase the risk of pregnancy.
  • Anatomical differences: Certain uterine shapes may interfere with the IUD's ability to function effectively.

​​Signs and Symptoms of IUD Failure

Signs and symptoms to watch for that can indicate an IUD has fallen out of place and is no longer effective include:

  • Abnormal pain, such as cramping, pelvic pain, or back pain
  • IUD strings that feel shorter or longer than usual or cannot be felt
  • Abnormal bleeding, such as heavy, irregular bleeding or breakthrough bleeding (spotting between periods)
  • Early pregnancy symptoms, such as missed periods, headaches, sore and enlarged breasts, nausea, vomiting, fatigue, and cramping

Potential IUD Side Effects

Even when functioning correctly, IUDs can cause side effects, especially in the first few months following IUD placement as the body adjusts to the device. Possible hormonal side effects include:

  • Breast tenderness
  • Headaches
  • Irregular periods or breakthrough bleeding (spotting between periods)
  • Lighter periods or no menstrual periods
  • Low libido
  • Mood changes

Possible side effects of copper IUDs include:

  • Heavier menstrual bleeding
  • Increased menstrual cramps
  • Irregular or unpredictable periods
  • Spotting between periods

Some IUD symptoms can be a sign of an infection or IUD misplacement. See a healthcare provider promptly if you experience any of the following:

  • Body aches
  • Chills
  • Difficulty finding the IUD strings
  • Fever
  • Severe cramps
  • Unusual vaginal discharge

How Do IUDs Work?

Hormonal and copper (nonhormonal) IUDs work in different ways to prevent pregnancy, as follows:

Hormonal IUDs

Hormonal IUDs (e.g., Mirena, Kyleena, Liletta, and Skyla) release a synthetic progestin (levonorgestrel) similar to the hormone progesterone the body produces. By releasing a small amount of progestin daily, hormonal IUDs thicken cervical mucus, forming a barrier that blocks sperm from reaching the egg. It also thins the uterine lining, making implantation less likely. In some cases, hormonal IUDs suppress ovulation.

Nonhormonal Copper IUDs

Nonhormonal copper IUDs, such as Paraguard, are wrapped in copper, which has spermicidal properties that make it harder for sperm to move and survive. By making the uterine environment inhospitable to sperm, the copper IUD effectively prevents sperm from fertilizing an egg.

How Long Your IUD Lasts

How long an IUD lasts depends on the type (hormonal vs. non-hormonal) and the brand. Here's how long you can expect an IUD to last:

  • Paragard (copper IUD): Up to 10 years
  • Mirena: Up to 8 years
  • Liletta: Up to 8 years
  • Kyleena: Up to 5 years
  • Skyla: Up to 3 years

Regardless of the type, a healthcare provider can remove your IUD at any time before its expiration date if you decide to change your contraception plan or are ready to become pregnant.

Complications Are Rare

IUDs are generally safe and well-tolerated. Most users experience only mild side effects, such as cramping or spotting, especially in the first few months after insertion. Although rare, complications can occur, such as:

  • Expulsion: There is a 1.49% chance per year of experiencing an IUD expulsion—when it slips or moves out of place. In simpler terms, out of 1,000 people using an IUD for one year, about 15 might experience an expulsion. Expulsion is rare and is most likely to occur within the first year after insertion, particularly in people with obesity, younger age (24 and under), or those who have recently given birth.
  • Infection: Bacteria introduced in the uterus during placement can cause an infection. The risk of pelvic infection is very low and typically occurs the first few weeks after insertion.
  • Perforation: IUD perforation is when the IUD punctures the uterine wall lining. Though rare—occurring in about 0.21% of people—this can happen during insertion or within the first year after placement.

Who Shouldn't Use an IUD?

While IUDs are safe and effective for most people, they may not be suitable for everyone. Certain medical conditions or circumstances can increase the risk of complications or IUD failure. You may need to consider alternative contraceptive options if you:

  • Are pregnant or suspect you might be pregnant
  • Have untreated pelvic infections, such as pelvic inflammatory disease (PID)
  • Experience unexplained vaginal bleeding
  • Have a uterine abnormality or condition that affects the shape of your uterus
  • Are allergic to copper (for the copper IUD) or are sensitive to the hormones in hormonal IUD
  • Have or recently had cervical, breast, or uterine cancer

Alternative Contraceptives

If an IUD isn't the right choice for you, there are many other contraceptive options available to fit your lifestyle and preferences. These include:

  • Birth control pills: Daily oral contraceptives contain hormones to prevent ovulation or pregnancy and regulate menstrual cycles.
  • Implant: A small rod inserted under the skin of the arm releases hormones for up to three years to prevent pregnancy.
  • Patch: A sticker patch on the buttocks, upper arm, or lower abdomen delivers hormones through the skin and into the bloodstream. It is worn for three weeks per month, with one patch-free week during menstruation.
  • Vaginal ring: This is a flexible ring worn inside the vagina for three weeks a month, with one week off during menstruation. The ring releases hormones to prevent pregnancy.
  • Injection: An injection of progestin prevents pregnancy for about three months.
  • Barrier methods: Condoms, diaphragms, sponges, and cervical caps prevent sperm from reaching the egg, preventing pregnancy.
  • Fertility awareness methods: This involves tracking the menstrual cycle and ovulation and avoiding intercourse during fertile days.
  • Sterilization: Tubal surgery (having your "tubes tied") or vasectomy are permanent contraception options for people who do not wish to have children in the future.

Summary

IUDs are a highly effective, long-lasting form of contraception with failure rates below 1%. They come in two types: hormonal, which releases progestin to prevent pregnancy, and copper, which is hormone-free and prevents sperm from fertilizing an egg and also works as emergency contraception. Beyond birth control, hormonal IUDs often provide therapeutic benefits for managing symptoms of endometriosis, PCOS, and heavy menstrual bleeding.

Complications, such as expulsion or infection, are rare, making IUDs a safe choice for most. However, they may not be suitable for people with certain medical conditions. Talk to a healthcare provider if you are considering an IUD. They can discuss the options and pros and cons and help decide if this is the right contraceptive method for you.

29 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. Lanzola EL, Ketvertis K. Intrauterine device. In: StatPearls. StatPearls Publishing; 2024.

  2. Planned Parenthood. IUD.

  3. MedlinePlus. Deciding about an IUD.

  4. Planned Parenthood. Hormonal IUDs.

  5. Guttmacher Institute. Contraception use in the United States by method.

  6. Centers for Disease Control and Prevention. Contraception: how effective are birth control methods?

  7. Planned Parenthood. How IUDs work as emergency contraception.

  8. Costescu DJ. Levonorgestrel-releasing intrauterine systems for long-acting contraception: current perspectives, safety, and patient counseling. Int J Womens Health. 2016;8:589-598. doi:10.2147/IJWH.S99705

  9. Planned Parenthood. IUD.

  10. Yucel N, Baskent E, Karamustafaoglu Balci B, Goynumer G. The levonorgestrel-releasing intrauterine system is associated with a reduction in dysmenorrhoea and dyspareunia, a decrease in CA 125 levels, and an increase in quality of life in women with suspected endometriosis. Aust N Z J Obstet Gynaecol. 2018;58(5):560-563. doi:10.1111/ajo.12773

  11. Creinin MD, Barnhart KT, Gawron LM, et al. Heavy menstrual bleeding treatment with a levonorgestrel 52-mg intrauterine device. Obstet Gynecol. 2023;141(5):971-978. doi:10.1097/AOG.0000000000005137

  12. Oguz SH, Yildiz BO. An Update on Contraception in Polycystic Ovary Syndrome. Endocrinol Metab (Seoul). 2021;36(2):296-311. doi:10.3803/EnM.2021.958

  13. MedlinePlus. Premenstrual dysphoric disorder.

  14. MedlinePlus. Premenstrual syndrome.

  15. Rapkin AJ, Korotkaya Y, Taylor KC. Contraception counseling for women with premenstrual dysphoric disorder (PMDD): current perspectives. Open Access J Contracept. 2019;10:27-39. doi:10.2147/OAJC.S18319

  16. Yacobson I, Wanga V, Ahmed K, et al. Clinical outcomes of intrauterine device insertions by newly trained providers: the ECHO trial experience. Contracept X. 2023;5:100092. doi:10.1016/j.conx.2023.100092

  17. Anthony MS, Zhou X, Schoendorf J, et al. Demographic, reproductive, and medical risk factors for intrauterine device expulsion. Obstet Gynecol. 2022;140(6):1017-1030. doi:10.1097/AOG.0000000000005000

  18. University of Washington Department of Obstetrics and Gynecology. IUD aftercare instructions.

  19. McNicholas C, Swor E, Wan L, Peipert JF. Prolonged use of the etonogestrel implant and levonorgestrel intrauterine device: 2 years beyond Food and Drug Administration-approved duration. Am J Obstet Gynecol. 2017;216(6):586.e1-586.e6. doi:10.1016/j.ajog.2017.01.036

  20. Merck Manual: Professional Version. Intrauterine devices (IUDs; IUD).

  21. Chu YQ, Tien CT, Ding DC. Early intrauterine pregnancy with an intrauterine device in place and terminated with spontaneous abortion: a case report. Medicine (Baltimore). 2024;103(16):e37843. doi:10.1097/MD.0000000000037843

  22. Venkataramani S, Elkott MM, Restrepo PO, et al. Intrauterine device migration: a diagnostic and management dilemma. Cureus. 2024;16(4):e57637. doi:10.7759/cureus.57637

  23. 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

  24. Planned Parenthood. What are the side effects of IUDs?

  25. MedlinePlus. Intrauterine devices.

  26. Reproductive Health Access Project. IUD information.

  27. Hubacher D. Intrauterine devices & infection: review of the literature. Indian J Med Res. 2014;140 Suppl(Suppl 1):S53-S57.

  28. Fassett MJ, Reed SD, Rothman KJ, et al. Risks of uterine perforation and expulsion associated with intrauterine devices. Obstet Gynecol. 2023;142(3):641-651. doi:10.1097/AOG.0000000000005299

  29. Centers for Disease Control and Prevention. Contraception and birth control methods.

How Effective Is an IUD for Pregnancy, PMS, and More? (2)

By Lindsay Curtis
Curtis is a writer with over 20 years of experience focused on mental health, sexual health, cancer care, and spinal health.

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