Many women consider the intrauterine device (IUD) as a form of birth control both before having a baby, and after.  This is because the IUD is reliable, safe, and is as effective as permanent sterilization making the IUD a desirable birth control option.

There Are Two Main Types Of IUDs Available On The Market Today: The Copper IUD And The Hormonal IUD.  

Both types of IUDs are small plastic T-shaped devices that are inserted into the uterus by a trained medical professional.  The copper IUD and the hormonal IUD act similarly in that they prevent the sperm from fertilizing the egg and also make it harder for implantation of an egg into the uterine lining.  

Benefits Of IUDs:

  • 99% effective at preventing pregnancy
  • Long acting (3-10 years depending on device) 
  • Reversible once device removed
    • Similar pregnancy rates as compared to non-IUD users
  • No need to rely on user adherence
  • Few reasons why women are not candidates for use
    • Anatomic abnormalities, active pelvic infection, current pregnancy, unexplained abnormal uterine bleeding, current breast cancer

Copper IUD

  • How does it work? 
    • Prevents the sperm from reaching the egg
    • Copper toxic to sperm
  • How long can it stay in?
    • 3-10 years depending on the device used 
  • Advantage of copper IUD over hormonal IUD
    • Can be used for emergency contraception if inserted within 5 days of unprotected sex
    • No hormone side effects
  • Disadvantage of copper IUD over hormonal IUD
    • Period may be heavier, longer or more painful 

Hormonal IUD (Progestin IUD)

  • How does it work? 
    • Contains levonorgestrel, a progestin hormone, that thickens cervical mucus and impairs implantation of an egg
    • Stops the lining of the uterus from growing as thick so an egg is less likely to implant
    • Local hormone effects. Very little hormone is absorbed into the bloodstream
    • Ovulation rates vary depending on device used
  • How long can it stay in?
    • 3-5 years depending on device used
  • Advantage of hormonal IUD over copper IUD
    • Slightly more effective at preventing pregnancy 
    • Progestin can make your period lighter or nearly absent and can reduce cramping during your cycle
    • Can be used for heavy menstrual bleeding or endometriosis
  • Disadvantage of hormonal IUD over copper IUD
    • Some women may still have hormone side effects of the very small amount of progestin hormone
    • Cannot be used as emergency contraception

This post was co-authored by Erin Manchuk, BScPharm, BCGP and Stephanie Liu, MD, MSc, CCFP, BHSc.

References

Phillips SJ, Tepper NK, Kapp N, et al. Progestogen-only contraceptive use among breastfeeding women: a systematic review. Contraception 2016;94:226–52.

Cleland K, Zhu H, Goldstuck N, et al. The efficacy of intrauterine devices for emergency contraception: a systematic review of 35 years of experience. Hum Reprod 2012;27:1994–2000

https://www.acog.org/Clinical-Guidance-and-Publications/Practice-Bulletins/Committee-on-Practice-Bulletins-Gynecology/Long-Acting-Reversible-Contraception-Implants-and-Intrauterine-Devices (Accessed 28 June 2019)

https://www.bayer.ca/omr/online/mirena-pm-en.pdf (Accessed 1 July 2019)