The Generalist: Long-Acting Reversible Contraception (LARCs)
Ben Shepherd, MD; Penny Wilson, MD; and Vanessa Cardy, MD
In this two-part segment, Aussies Ben Shepherd and Penny Wilson bring us up to speed on topics that are near global in their appeal and use: emergency contraception and long-acting reversible contraception (LARC)
- The American College of Obstetricians and Gynecologists (ACOG) recommends LARCs as “the most effective reversible contraceptive methods … including for adolescents”
- Perfect use and real-world use are almost the same with LARCs:
- Rates of unexpected pregnancy are well below 1%.
- For oral contraceptive pills (OCPs), pregnancy rates = 9%.
- Two main forms of LARCs
- IUD
- Copper
- Works by inhibiting fertilization (copper is “toxic to sperm”)
- Levonorgestrel IUD (Mirena, Skyla, Kyleena, Jaydess)
- Thickens the cervical mucus to inhibit sperm motility
- Causes atrophy of the endometrial lining
- Can sometimes (not always) inhibit ovulation
- Etonogestrel subdermal implant (Nexplanon or Implanon)
- Similar to levonorgestrel IUD, but more effective inhibition of ovulation
- Barriers to LARC use
- Cultural expectations and patient preferences
- Cost and access to skilled inserters
- Health provider knowledge and attitudes
- History of IUDs:
- Early IUDs in the 1970s caused PID and tubal infertility.
- Modern IUDs do not.
- Side effects
- LARCs are generally well tolerated.
- Changes in bleeding pattern and cramping can occur:
- Heavy or painful bleeding; highest risk with copper IUD
- Levonorgestrel IUD is very unlikely to cause increased bleeding, usually significantly decreased or absent bleeding
- Can settle in first few months
- Impact of implant varies
- Hormonal options can cause progestin side effects:
- More likely with implant than with IUD
- Headaches, acne, change in libido, appetite or weight change
- Contraindications
- IUDs
- Uterine and cervical infections
- Active cervical cancer
- Concerning uterine bleeding
- Uterine anatomic anomalies
- Levonorgestrel IUD/etonogestrel implant
- Current or recent breast cancer
- Severe liver disease
- Refer to the CDC for the full list of risks and benefits:
PEARL: LARCs are well tolerated by most women; they are significantly more effective and have fewer contraindications than other hormone-based forms of contraception.
David G., M.D. - October 25, 2021 10:28 AM
Could you comment whether these contraceptives qualify as a risk factor for thromboembolism? My understanding is that they do not they are not estrogen-based
Penny W. - October 25, 2021 7:04 PM
Hi David. Yes that is more or less correct. According to the CDC MEC, progestin only contraceptives are considered category "2" for people with risk factors for VTE or acute VTE. As in, "benefits outweigh risks". As opposed to combined estrogen-progestin contraceptives which are category "4", ie, contraindicated.