From the Research
The use of Mirena (levonorgestrel) intrauterine device can increase the risk of developing ovarian cysts, with approximately 2.0 to 2.4% of users developing ovarian cysts during the first year of use, as reported in the most recent and highest quality study 1.
Key Findings
- The study found that ovarian cysts were present in 1.6% of women at screening and 1.1-2.4% at each subsequent visit during the 3-year clinical trial of LNG-IUS 13.5mg 1.
- The majority of the cysts were >30 to ≤50 mm in size, and the likelihood of cyst persistence increased for cysts >50mm 1.
- The small and diminishing number of persistent cysts, decreasing to 0% from 9 to 12 months, suggests that they were functional in nature 1.
Clinical Implications
- The increased risk of ovarian cysts with Mirena use is likely due to the alteration of normal hormonal patterns that control ovulation, leading to incomplete follicular development or delayed follicle rupture 1.
- Despite this side effect, Mirena remains a highly effective contraceptive option with many benefits, and the risk of cysts is generally considered manageable for most women.
- Women using Mirena should be aware of the potential risk of ovarian cysts and report any symptoms such as pelvic pain, abdominal bloating, or irregular bleeding to their healthcare provider.
Comparison with Other Studies
- The findings of the study 1 are consistent with previous studies that have reported an increased risk of ovarian cysts with the use of levonorgestrel-releasing intrauterine systems 2, 3.
- However, the study 1 provides more recent and detailed information on the prevalence and persistence of ovarian cysts with Mirena use, making it the most relevant and reliable source of information on this topic.