May 10, 2023
By Shannon Blemings, Drexel University College of Medicine

What is LARC?

Long-acting reversible contraceptives (LARCs) can be a great option for pregnancy prevention. LARC options include hormonal intrauterine devices (IUDs), copper IUDs and hormonal subdermal implants. Other than surgical sterilization, LARCs are the most effective option for preventing unintended pregnancy.¹ In addition to their effectiveness, benefits of LARC include fewer user responsibilities (as compared to daily pills, monthly ring replacements or tri-monthly injections) and reversibility (as opposed to permanent surgical sterilization). They can be removed at any time by a health care provider.

IUDs

A hormonal IUD is a T-shaped bar that sits inside the uterus against the cervix. They work by releasing a steady concentration of hormone called levonorgestrel, a synthetic progestin, which prevents ovulation.² If there is no egg, fertilization cannot take place and pregnancy is prevented. When used perfectly, hormonal IUDs are 99.4-99.9% effective at preventing pregnancy, meaning less than 1% of users will become pregnant after one year of use.³ Users should be counseled before insertion that hormonal IUDs can cause irregular or absent menstrual periods. They come in two sizes with different dosages of hormones to accommodate a range of users.

• Skyla is small (28 mm x 30 mm), has the smallest dose of hormones, and is approved and effective for up to three years.⁴
• Kyleena is the same size as Skyla, but with a larger dose, and it is approved and effective for up to five years.⁴
• Liletta is larger (32 mm x 32 mm), with a larger dose of hormones, and it is approved and effective for six years.⁴, ⁵
• Mirena is the same size as Liletta, has the largest dose of hormones, and is approved and effective for up to eight years.², ⁴

Copper IUDs sit in the same place inside the uterus as hormonal IUDs. You may hear them referred to by their brand name, Paragard. They are made of plastic and copper, and may work by creating an inflammatory reaction in the uterus that inhibits sperm meeting the egg.⁵ When the sperm and egg cannot meet, fertilization cannot occur, and pregnancy is prevented. When used perfectly, the copper IUD is 99.4-99.9% effective² and is approved for up to 10 years⁶, though studies suggest it remains effective for up to 12 years.⁷ They should not be used in people with an allergy to copper. They can also make menstrual periods heavier, so are usually avoided in people with very heavy periods.

Implants

Subdermal implants are flexible plastic bars that sit just beneath the skin in the upper arm. The implant currently available in the United States is called Nexplanon, which replaced its predecessor called Implanon. The implant releases a steady amount of a hormone called etonogestrel, another synthetic progestin. Like hormonal IUDs, this inhibits egg release, thereby preventing pregnancy. It also thickens cervical mucus, which prevents sperm from getting through.⁸ When used perfectly, it is 99.9% effective.⁹ It is FDA-approved for up to three years, but several studies have shown it can be effective up to five years.¹⁰,¹¹,¹² Like the hormonal IUD, the progestin in the implant can lead to irregular or absent periods.

Discussion

LARCs can be a great option and are offered as first-line contraceptives because of their superior effectiveness. However, it is important for providers to always engage in shared decision-making and patient-centered discussions surrounding birth control options. People may have various reasons for declining LARC including cost¹³, pregnancy ambivalence¹⁴, desire for a regular menstrual cycle, ability to discontinue use without health care provider intervention, perceived pain associated with insertion, lack of STI prevention, and many others. It is important to remember that “most effective” does not equal “best” for everyone. LARC is simply one tool in the toolbox for pregnancy prevention.

Sources/Resources:

• Effectiveness of birth control methods. ACOG. (n.d.). Retrieved April 26, 2023, from acog.org/womens-health/infographics/effectiveness-of-birth-control-methods
• How does mirena® work? Mirena US. (n.d.). Retrieved October 15, 2022, from mirena-us.com/about-mirena/how-does-mirena-work
• Iud Birth Control Options: Learn About Copper Iuds & hormonal iuds. Bedsider. (n.d.). Retrieved October 15, 2022, from bedsider.org/birth-control/iud
• Watkins, R. (2022, June 16). Which IUD should I get? Bedsider Providers. Retrieved October 15, 2022, from providers.bedsider.org/articles/which-iud-should-i-get
• Liletta HCP. Learn More About LILETTA® IUS (also known as IUD) | Official Site. (n.d.). Retrieved October 15, 2022, from liletta.com/about
• Ortiz, M. E., Croxatto, H. B., & Bardin, C. W. (1996). Mechanisms of action of intrauterine devices. Obstetrical & Gynecological Survey, 51(12). doi.org/10.1097/00006254-199612000-00014
• Birth control that's 100% hormone-free. Paragard® IUD. (n.d.). Retrieved October 15, 2022, from paragard.com/what-is-paragard/
• Croxatto, H. B. (2002). Mechanisms that explain the contraceptive action of progestin implants for women. Contraception, 65(1), 21–27. doi.org/10.1016/s0010-7824(01)00294-3
• Birth control implant (Nexplanon): Costs, benefits & side effects. Bedsider. (n.d.). Retrieved October 15, 2022, from bedsider.org/birth-control/implant
• Ali, M., Akin, A., Bahamondes, L., Brache, V., Habib, N., Landoulsi, S., & Hubacher, D. (2016). Extended use up to 5 years of the Etonogestrel-releasing subdermal contraceptive implant: Comparison to levonorgestrel-releasing subdermal implant. Human Reproduction, 31(11), 2491–2498. doi.org/10.1093/humrep/dew222
• Ali, M., Bahamondes, L., & Bent Landoulsi, S. (2017). Extended effectiveness of the Etonogestrel-releasing contraceptive implant and the 20 µg levonorgestrel-releasing intrauterine system for 2 years beyond U.S. Food and Drug Administration product labeling. Global Health: Science and Practice, 5(4), 534–539. doi.org/10.9745/ghsp-d-17-00296
• McNicholas, C., Swor, E., Wan, L., & Peipert, J. F. (2017). Prolonged use of the Etonogestrel implant and levonorgestrel intrauterine device: 2 Years beyond food and drug administration–approved duration. American Journal of Obstetrics and Gynecology, 216(6). doi.org/10.1016/j.ajog.2017.01.036
• Yarger, J., Schroeder, R., Blum, M., Cabral, M. A., Brindis, C. D., Perelli, B., & Harper, C. C. (2021). Concerns about the cost of contraception among young women attending Community College. Women's Health Issues, 31(5), 420–425. doi.org/10.1016/j.whi.2021.03.006
• Higgins, J. A. (2017). Pregnancy ambivalence and long-acting reversible contraceptive (Larc) use among young adult women: A qualitative study. Perspectives on Sexual and Reproductive Health, 49(3), 149–156. doi.org/10.1363/psrh.12025