What is the difference between Mirena (levonorgestrel) and Liletta (levonorgestrel)?

Mirena and Liletta: Key Differences

Both Mirena and Liletta contain the same 52 mg dose of levonorgestrel and are equally effective for contraception, but they differ primarily in their FDA-approved duration of use and therapeutic indications—Mirena is approved for 5 years (though effective up to 7-8 years) and has additional FDA approval for treating heavy menstrual bleeding, while Liletta is approved for only 3 years of contraceptive use. 1

Similarities Between the Devices

Hormonal Content and Contraceptive Efficacy

• Both devices contain identical 52 mg levonorgestrel reservoirs 1
• Both maintain failure rates of less than 1% during their approved use periods, making them among the most effective contraceptive methods available 1, 2
• The mechanism of action is identical—preventing fertilization by inhibiting sperm motility and thickening cervical mucus 1

Safety Profile

• Both share the same general safety profile as highly safe reversible contraceptive methods 2
• The CDC notes that the risk of pelvic infection is small and limited to the first 20-21 days after insertion for both devices 2
• Both have the same contraindications, including current or recent (within 3 months) pelvic inflammatory disease 2
• Both are safe for nulliparous adolescents and do not cause tubal infertility 1
• Rapid return to fertility occurs after removal of either device 1

Critical Differences

FDA-Approved Duration

• Mirena is FDA-approved for 5 years of use, with clinical evidence demonstrating efficacy extending to 7-8 years 1, 2
• Liletta is FDA-approved for only 3 years of use 1
• For extended Mirena use (years 6-8), the cumulative failure rate remains extremely low at 0.68%, with a 3-year Pearl Index of 0.28 3

Therapeutic Indications Beyond Contraception

• Mirena has FDA approval for treating menorrhagia (heavy menstrual bleeding) and is recommended as first-line medical management by the American College of Radiology 2
• Liletta has no FDA-approved therapeutic indications beyond contraception 1

Effects on Menstrual Bleeding

• While both devices reduce menstrual bleeding, Mirena produces a more marked reduction due to its higher daily hormonal release rate 2
• Many Mirena users experience amenorrhea or infrequent bleeding 2
• During extended Mirena use through 8 years, approximately half of women experience amenorrhea or infrequent bleeding 3

Hormonal Release Rates Over Time

• Mirena's levonorgestrel release rate decreases from approximately 21 µg/day after insertion to about 7.0 µg/day after 8 years 4
• After 8 years of Mirena use, average plasma levonorgestrel concentrations remain at 100 ng/L, which is sufficient for contraceptive efficacy 4

Clinical Decision-Making Algorithm

For contraception alone in women who want 3-5 years of coverage: Either device is appropriate, though Mirena offers the option of extended use if desired 1, 2

For contraception with heavy menstrual bleeding or dysmenorrhea: Choose Mirena, as it is FDA-approved for this indication and produces more marked bleeding reduction 2

For women desiring maximum duration without device replacement: Choose Mirena, which maintains efficacy through 8 years 1, 3

For adolescents requiring long-term menstrual suppression where estrogen is contraindicated: Mirena is the preferred choice given its therapeutic approval and greater bleeding reduction 1, 2

Common Pitfalls to Avoid

• Do not assume Liletta has the same approved duration as Mirena—it is only approved for 3 years despite having the same hormonal content 1
• Do not use Liletta for treating heavy menstrual bleeding, as it lacks FDA approval for this indication 1, 2
• Counsel patients that Mirena can be safely continued beyond 5 years up to 8 years based on high-quality evidence, with user satisfaction rates of 98.7% at 8 years 3
• Remember that both devices may cause frequent intermenstrual bleeding and spotting during the first 3-4 months, but this typically resolves 5