In the treatment of patients with organic disease and heavy menstrual bleeding and/or dysmenorrhea, the use of levonorgestrel-releasing intrauterine system (LNG-IUS) attenuates chronic pelvic pain, according to a study. However, it appears to confer an increased risk of expulsion for some women.

The prospective, open-label study included 595 Japanese patients initiating the LNG-IUS for heavy menstrual bleeding and/or dysmenorrhea. These women were followed for 12 months to assess the safety profile of LNG-IUS, the primary study endpoint. Secondary endpoints included changes from baseline in menstrual blood loss (based on bleeding days) and dysmenorrhea, both of which were graded on a visual analogue scale (VAS).

Many of the women had underlying conditions such as adenomyosis (39.5 percent), uterine leiomyoma (30.8 percent), or endometriosis (12.9 percent).

The frequency of adverse drug reactions (ADRs) was 59.7 percent, while that of serious ADRs was 0.3 percent. The most common ADRs were metrorrhagia (48.9 percent), procedural pain (14.1 percent), and ovarian cyst (6.2 percent).

At 12 months, 8.7 percent of the women had experienced expulsion. The risk of expulsion was high among women with obesity (body mass index ≥25 kg/m2) and in the presence of adenomyosis and uterine cavity length ≥8 cm.

LNG-IUS led to a decrease in dysmenorrhea, with the corresponding median VAS score dropping from 46.5 at insertion to 1.0 at 12 months. Parallel improvements in chronic pelvic pain and painful defecation were also observed.