What is the Levonorgestrel (intrauterine device) IUD?

Levonorgestrel Intrauterine Device (IUD)

The levonorgestrel intrauterine device (IUD) is a highly effective, long-acting reversible contraceptive method with a failure rate of less than 1% that provides continuous contraception for 3-7 years depending on the specific product, while also offering therapeutic benefits for conditions like menorrhagia and dysmenorrhea. 1

Types and Duration of Use

• There are currently multiple levonorgestrel-releasing IUDs approved in the United States:
  • 52 mg levonorgestrel IUD (Mirena) - approved for 5 years, but effective for up to 7 years 1
  • 13.5 mg levonorgestrel IUD (Skyla) - approved for 3 years 1
  • 52 mg levonorgestrel IUD (Liletta) - approved for 3 years 1

Mechanism of Action

• The primary mechanism of action of levonorgestrel IUDs is preventing fertilization by:
  • Inhibiting sperm motility 1
  • Thickening cervical mucus 1
• All mechanisms occur before implantation, and inhibiting implantation is not believed to be a primary mechanism of action 1

Effectiveness

• Levonorgestrel IUDs are among the most effective contraceptive methods available with:
  • Typical and perfect use failure rates of less than 1% 1
  • Pearl pregnancy rate in studies of 0.0-0.2 per 100 women-years 2
  • Extremely low ectopic pregnancy rate of 0.02 per 100 woman-years 2

Benefits Beyond Contraception

• Reduction in menstrual blood loss (up to 90% from pretreatment levels in the first year) 2
• Many women experience lighter periods or amenorrhea 1
• Significant improvement in dysmenorrhea 2
• Increased body iron stores due to reduced menstrual blood loss 2
• Therapeutic benefits for conditions such as:
  • Menorrhagia (heavy menstrual bleeding) 3, 4
  • Symptomatic fibroids 4, 5
  • Endometriosis 4, 5
  • Endometrial protection 3, 4
• Particularly useful for adolescents with medical conditions requiring long-term menstrual suppression where estrogen is contraindicated 1

Safety Profile

• Safe for nulliparous adolescents 1
• Does not cause tubal infertility in nulliparous women 1
• Rapid return to fertility after removal 1
• Small risk of pelvic infection only around the time of insertion (first 20-21 days) 1
• Beyond the initial insertion period, IUDs do not increase rates of pelvic inflammatory disease above baseline 1
• HIV infection and immunosuppression are not contraindications to IUD use 1

Common Side Effects and Management

• Menstrual pattern changes are the most common side effect:
  • Initial irregular spotting is common in the first 2-3 months 2
  • Over time, most users experience reduced bleeding or amenorrhea 1
• Proper counseling about expected bleeding changes is critical for improving compliance and reducing premature removal 2, 4

Contraindications

• Current or recent (past 3 months) pelvic inflammatory disease 1
• Current gonorrhea, chlamydia, or purulent cervicitis 1
• Pregnancy 1
• Uterine anomalies that distort the uterine cavity in a manner incompatible with IUD insertion 1

Special Considerations

• Can be inserted in asymptomatic adolescents at high risk of STIs with screening on the day of insertion 1
• Treatment of newly diagnosed STIs can be provided without IUD removal, as long as the patient improves with treatment 1
• For HIV-infected individuals, the benefits of using an IUD generally outweigh theoretical or proven risks 1
• The copper IUD can be used as emergency contraception within 5 days of unprotected intercourse, but the levonorgestrel IUD is not approved for this purpose 1

Clinical Pearls

• Thorough counseling about expected bleeding pattern changes is essential to improve continuation rates 2, 4
• Immediate postpartum insertion of IUDs is safe and effective, removing barriers to care 1
• For adolescents who need highly effective contraception that is user- and coitus-independent, the levonorgestrel IUD is an excellent choice 1
• Screening for gonorrhea and chlamydia can be performed at the same time as insertion 1