Evaluation of the Presence and Persistence of Ovarian Cysts in Users of a New Low-Dose Levonorgestrel-Releasing Intrauterine Contraceptive System over 5 Years

OBJECTIVE: To assess presence and persistence of ovarian cysts in users of a new levonorgestrel-releasing intrauterine contraceptive system (LNG-IUS 12 [12 mu g average daily release rate over 1 year, 19.5 mg total content]). STUDY DESIGN: A phase 3 study assessed the efficacy and safety of LNG-IUS 12 use in healthy women requesting contraception. Ul-trasonography was performed at screening, baseline, and periodically for up to 5 years. Ovarian cysts were defined as cystic structures >30 mm in diameter and/or not having the appearance of a follicle. RESULTS: A total of 13,306 transvaginal ultrasounds were performed in 1,452 women (mean age, 27.1 years). Cysts were imaged in 1.6% of women at screening. Thereafter, the presence of cysts was 1.5-4.8%. In all, 170 incident cysts were imaged from baseline through month 9; 78% of those measured >30 to <= 50 mm. Persistence from one examination to the next during year 1 was 9.4% (15/159), with baseline to 3 months=16%, 3-6 months =12%, 6-9 months =9%, and 9-12 months = 4%. Persistence was higher for cysts >50 mm (17%). CONCLUSION: Ovarian cysts were present in 1.6% of women at screening, 3.0-4.8% of LNG-IUS 12 users during year 1, and 1.9-3.4% during years 2-5. The majority were >30 to <= 50 mm. The small and diminishing number of persistent cysts suggests the majority were functional and not clinically relevant.