Association of baseline bleeding pattern on amenorrhea with levonorgestrel intrauterine system use

This study aims to evaluate the effect of baseline bleeding patterns on rates of amenorrhea reported at 12 months in levonorgestrel (LNG) 52 mg intrauterine system (IUS) users. We also assessed the effect of baseline bleeding patterns at 3 and 6 months postinsertion.

In this secondary analysis of the Contraceptive CHOICE Project, we included participants who had an LNG-IUS inserted within 1 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 6 months. We used chi-square and multivariable logistic regression to assess the association of baseline bleeding pattern with amenorrhea while controlling for confounding variables.

Of 1802 continuous 12-month LNG-IUS users, amenorrhea was reported by 4.9%, 14.8% and 15.4% of participants at 3, 6 and 12 months, receptively. Participants with light baseline bleeding or short duration of flow reported higher rates of amenorrhea at 3 and 6 months postinsertion (p<.03), while LNG-IUS users with heavy or prolonged flow were less likely to report amenorrhea at 3 and 6 months (p<.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 (OR_adj, 0.36; 95% CI, 0.16-0.69).

Women with heavier menstrual bleeding are less likely than women with moderate flow to report amenorrhea following 12 months of LNG-IUS use.

Baseline heavy menstrual flow reduces the likelihood of amenorrhea with LNG-IUS use, information that could impact contraceptive counseling. Anticipatory counseling can improve method satisfaction and continuation, an important strategy to continue to reduce unintended pregnancy and abortion rates.