Safe Extended Use of Levonorgestrel 52-mg IUDs

Andrew M. Kaunitz, MD


November 11, 2022

This transcript has been edited for clarity.

IUDs are now used by more than 15% of US contraceptors. The majority of these IUDs release the progestin levonorgestrel (LNG). Extended use of IUDs allows users to continue their intrauterine contraception with fewer removal and insertion procedures. Two recently published clinical trials assessed the extended use of full-size IUDs which contain 52 mg of LNG, with brand names Mirena or Liletta.

In the study assessing Mirena IUDs, investigators followed women who completed 8 years of use. The cumulative failure rate for years 6 through 8 was less than 0.7%. Of the two pregnancies identified during these 3 years, one had an uncertain implantation site and resolved spontaneously. A second pregnancy was ectopic and resolved with methotrexate treatment.

In the Liletta 8-year extension trial, two pregnancies were identified during years 7 and 8. The cumulative failure rate from the time of IUD insertion through year 8 was 1.3%. With respect to bleeding profiles during extended use of LNG 52 IUDs in these two trials, some 40%-50% of women reported either no bleeding or infrequent bleeding during extended IUD use.

The data from these trials confirm that Mirena and Liletta remain highly effective through 8 years of use. Recently, Mirena was approved for up to 8 years of use, and before the end of 2022, the FDA is expected to also approve Liletta for up to 8 years.

Two last points:

  • Although IUDs are highly effective in preventing ectopic as well as intrauterine pregnancies, clinicians identifying a pregnancy in a patient using an IUD should recognize the increased risk for an ectopic in this setting, and proceed with vaginal ultrasound as well as quantitative HCG assessment.

  • The extended contraceptive efficacy demonstrated in these two trials of LNG 52 IUDs may not apply to effectiveness in suppressing heavy menstrual bleeding (HMB). In my experience, among women using IUDs specifically for HMB, maintaining good bleeding control may require changing out IUDs every 3-5 years.

I am Andrew Kaunitz. Please take care of yourself — and each other.

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