BACKGROUND: Intrauterine devices, including levonorgestrel-releasing and copper devices, are highly effective long-acting reversible contraceptives. Potential risks associated with intrauterine devices are low and include uterine perforation and device expulsion.
OBJECTIVE: To evaluate the risk of perforation and expulsion associated with levonorgestrel-releasing devices versus copper in clinical practice in the United States.
STUDY DESIGN: APEX-IUD was a retrospective cohort study of women aged ≤50 years with an intrauterine device insertion during 2001-2018, and information on intrauterine device type, as well as patient and medical characteristics. Four research sites with access to electronic health records contributed data for the study: three Kaiser Permanente integrated healthcare systems (Northern California, Southern California, and Washington) and one using data from a healthcare information exchange in Indiana (Regenstrief Institute). Perforation was classified as any extension of the device into or through the myometrium. Expulsion was classified as complete (not visible in uterus or abdomen or patient-reported) or partial (any portion in cervix or malpositioned). We estimated, by intrauterine device type, crude incidence rates and crude cumulative incidence. Perforation and expulsion risk comparing levonorgestrel devices to copper was estimated using Cox proportional hazards regression with propensity score overlap weighting to adjust for confounders.
RESULTS: Among the 322,898 women included in this analysis, the incidence (95% confidence interval) of perforation per 1,000 person-years was 1.64 (1.53-1.76) for levonorgestrel devices and 1.27 (1.08-1.48) for copper devices; cumulative 1-year and 5-year crude incidence (95% confidence interval), respectively, was 0.22% (0.20%-0.24%) and 0.63% (0.57%-0.68%) for levonorgestrel devices and 0.16% (0.13%-0.20%) and 0.55% (0.44%-0.68%) for copper devices. The incidence (95% confidence interval) of expulsion per 1,000 person-years was 13.95 (13.63-14.28) for levonorgestrel devices and 14.08 (13.44-14.75) for copper devices; cumulative 1-year and 5-year crude incidence (95% confidence interval), respectively, was 2.30% (2.24%-2.36%) and 4.52% (4.40%-4.65%) for levonorgestrel devices and 2.30% (2.18%-2.44%) and 4.82% (4.56%-5.10%) for copper devices. Adjusted hazard ratios (95% confidence intervals) were 1.49 (1.25-1.78) for perforation and 0.69 (0.65-0.73) for expulsion comparing levonorgestrel to copper devices.
CONCLUSIONS: After adjusting for potential confounders, levonorgestrel devices were associated with an increased risk of uterine perforation and a decreased risk of expulsion relative to copper devices. Given that the absolute numbers of these events are low in both groups, these differences may not be clinically meaningful.
