Relationship of parity and prior cesarean delivery to levonorgestrel 52 mg intrauterine system expulsion over 6 years

Objective: Assess the relationship between parity and prior route of delivery to levonorgestrel 52 mg intrauterine system (IUS) expulsion during the first 72 months of use. Study Design: We evaluated women enrolled in the ACCESS IUS multicenter, Phase 3, open-label clinical trial of the Liletta levonorgestrel 52 mg IUS. Investigators evaluated IUS presence at 3 and 6 months after placement and then every 6 months and during unscheduled visits. We included women with successful placement and at least one follow-up assessment. We evaluated expulsion rates based on obstetric history; for prior delivery method subanalyses, we excluded 12 participants with missing delivery data. We determined predictors of expulsion using multivariable regression analyses. Results: Of 1714 women with IUS placement, 1710 had at least one follow-up assessment. The total population included 986 (57.7%) nulliparous women. Sixty-five (3.8%) women experienced expulsion within 72 months, 50 (76.9%) within the first 12 months. Expulsion rates among nulliparous women (22/986 [2.2%]) or parous women with any pregnancy ending with a Cesarean delivery (6/195 [3.1%]) differed from parous women who only experienced vaginal deliveries (37/517 [7.2%]) (p < 0.001). In multivariable regression, obesity (adjusted odds ratio [aOR] 2.2, 95% confidence interval [CI] 1.3–3.7), parity (aOR 2.2, 95% CI 1.2–4.1), and non-white race (aOR 1.8, 95% CI 1.1–3.2) predicted expulsion. Among parous women, obesity (aOR 2.2, 95% CI 1.2–4.2) increased the odds and having ever had a cesarean delivery (aOR 0.4, 95% CI 0.1–0.9) decreased the odds of expulsion. Conclusion: IUS expulsion occurs in less than 4% of users over the first 6 years of use and occurs mostly during the first year. Expulsion is more likely among obese and parous women. Implications: Levonorgestrel 52 mg intrauterine system expulsion occured more commonly in parous than nulliparous women; the increase in parous women is primarily in women who had vaginal deliveries only. The association between obesity, delivery route, and IUS expulsion needs further elucidation.