Ovarian cysts: presence and persistence with use of a 13.5mg levonorgestrel-releasing intrauterine system

Abstract

Objective: The aim of this study was to assess the presence of ovarian cysts in women using a new low-dose levonorgestrel-releasing intrauterine contraceptive system (LNG-IUS 13.5mg [total content]).

Study design: A Phase 3 study assessed LNG-IUS 13.5mg use in healthy women with regular menstrual cycles who requested contraception. Transvaginal ultrasonography was performed at screening, baseline, and 3, 6, 9, 12, 18, 24, 30, and 36 months after placement.

Results: A total of 1432 women, mean age 27.2±4.8 years, were studied. A total of 10,446 transvaginal ultrasound examinations were performed over 3 years. Ovarian cysts were present in 1.6, 1.1, 2.3, 2.1, 2.4, 2.0, 2.1, 2.2, 1.9, and 2.1% of participants at screening, baseline, and Months 3, 6, 9, 12, 18, 24, 30, and 36, respectively. One hundred first-time ovarian cysts were identified from baseline through Month 9. The size distribution through Month 12 was ≤30 mm (13%), >30 to ≤50 mm (74%), >50 to ≤80 mm (11%), and >80 mm (0%). The overall persistence of ovarian cysts from one examination to the next in Year 1 was 12% (11/90 with follow-up). Cyst persistence was 36% from baseline to 3 months, 13% from 3 to 6 months, 10% from 6 to 9 months, and 0% from 9 to 12 months. The likelihood of cyst persistence increased for cysts >50mm (36%) as compared to those ≤50 mm (8%).

Conclusion: Ovarian cysts were present in 1.6% of women at screening, 2.0 to 2.4% of LNG-IUS 13.5mg users during Year 1, and 1.9 to 2.1% during Years 2 and 3. The majority were >30 to ≤50 mm in size. The small and diminishing number of persistent cysts-decreasing to 0% from 9 to 12 months-suggests that they were functional in nature.

Implications: Transvaginal ultrasound follow-up of women during a 3-year clinical trial of LNG-IUS 13.5mg showed that ovarian cysts were present in 1.6% of participants at screening and 1.1-2.4% at each subsequent visit. Eighty-eight percent were ≤5cm, with none >8cm. No ovarian cysts persisted beyond Month 9, suggesting a functional etiology.

Trial registration: ClinicalTrials.gov NCT00528112.

Keywords: Intrauterine contraception; Intrauterine device; Intrauterine system; LNG-IUS; Levonorgestrel; Ovarian cyst.