Association of Baseline Bleeding Pattern on Amenorrhea with Levonorgestrel Intrauterine System Use

Abstract

OBJECTIVE To evaluate the effect of baseline bleeding patterns on rates of amenorrhea reported at 12 months in LNG (levonorgestrel) 52 mg IUS (intrauterine system) users. We also assessed the effect of baseline bleeding patterns at three and six months post-insertion. STUDY DESIGN In this secondary analysis of the Contraceptive CHOICE Project, we included participants who had a LNG-IUS inserted within one month of enrollment and continued use for 12 months. Using 12-month telephone survey data, we defined amenorrhea at 12 months of use as no bleeding or spotting during the previous six months. We used chi-square and multivariable logistic regression to assess the association of baseline bleeding pattern with amenorrhea while controlling for confounding variables. RESULTS Of 1802 continuous 12-month IUS users, amenorrhea was reported by 4.9%, 14.8% and 15.4% of participants at three, six, and 12 months, receptively. Participants with light baseline bleeding or short duration of flow reported higher rates of amenorrhea at three and six months post-insertion (p<0.03), while LNG-IUS users with heavy or prolonged flow were less likely to report amenorrhea at 3 and 6 months (p<0.03). In a multivariable analysis, participants with self-reported heavy bleeding at baseline were less likely to report amenorrhea at 12 months than those who reported moderate bleeding (ORadj, 0.36; 95% CI, 0.16–0.69). CONCLUSION Women with heavier menstrual bleeding are less likely than women with moderate flow to report amenorrhea following 12 months of LNG-IUS use.