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Design of the Association of Uterine Perforation and Expulsion of Intrauterine Device study: a multisite retrospective cohort study.

  • Anthony, Mary S1
  • Reed, Susan D2
  • Armstrong, Mary Anne3
  • Getahun, Darios4
  • Gatz, Jennifer L5
  • Saltus, Catherine W6
  • Zhou, Xiaolei7
  • Schoendorf, Juliane8
  • Postlethwaite, Debbie A3
  • Raine-Bennett, Tina3
  • Fassett, Michael J4
  • Peipert, Jeffrey F9
  • Ritchey, Mary E7
  • Ichikawa, Laura E10
  • Lynen, Richard11
  • Alabaster, Amy L3
  • Merchant, Maqdooda3
  • Chiu, Vicki Y4
  • Shi, Jiaxiao M4
  • Xie, Fagen4
  • And 9 more
  • 1 RTI Health Solutions, Research Triangle Park, NC. Electronic address: [email protected]
  • 2 Kaiser Permanente Washington, Seattle, WA; University of Washington, Seattle, WA.
  • 3 Kaiser Permanente Northern California, Oakland, CA.
  • 4 Kaiser Permanente Southern California, Pasadena, CA.
  • 5 Regenstrief Institute, Indianapolis, IN. , (India)
  • 6 RTI Health Solutions, Waltham, MA.
  • 7 RTI Health Solutions, Research Triangle Park, NC.
  • 8 Bayer AG, Bayer Oy, Espoo, Finland. , (Finland)
  • 9 Regenstrief Institute, Indianapolis, IN; Indiana University, Indianapolis, IN. , (India)
  • 10 Kaiser Permanente Washington, Seattle, WA.
  • 11 Bayer AG, Whippany, NJ.
  • 12 Bayer AG, Wuppertal, Germany. , (Germany)
  • 13 Bayer AG, Berlin, Germany. , (Germany)
Published Article
American journal of obstetrics and gynecology
Publication Date
Jun 01, 2021
DOI: 10.1016/j.ajog.2021.01.003
PMID: 33460585


Intrauterine devices are effective and safe, long-acting reversible contraceptives, but the risk of uterine perforation occurs with an estimated incidence of 1 to 2 per 1000 insertions. The European Active Surveillance Study for Intrauterine Devices, a European prospective observational study that enrolled 61,448 participants (2006-2012), found that women breastfeeding at the time of device insertion or with the device inserted at ≤36 weeks after delivery had a higher risk of uterine perforation. The Association of Uterine Perforation and Expulsion of Intrauterine Device (APEX-IUD) study was a Food and Drug Administration-mandated study designed to reflect current United States clinical practice. The aims of the APEX-IUD study were to evaluate the risk of intrauterine device-related uterine perforation and device expulsion among women who were breastfeeding or within 12 months after delivery at insertion. We aimed to describe the APEX-IUD study design, methodology, and analytical plan and present population characteristics, size of risk factor groups, and duration of follow-up. APEX-IUD study was a retrospective cohort study conducted in 4 organizations with access to electronic health records: Kaiser Permanente Northern California, Kaiser Permanente Southern California, Kaiser Permanente Washington, and Regenstrief Institute in Indiana. Variables were identified through structured data (eg, diagnostic, procedural, medication codes) and unstructured data (eg, clinical notes) via natural language processing. Outcomes include uterine perforation and device expulsion; potential risk factors were breastfeeding at insertion, postpartum timing of insertion, device type, and menorrhagia diagnosis in the year before insertion. Covariates include demographic characteristics, clinical characteristics, and procedure-related variables, such as difficult insertion. The first potential date of inclusion for eligible women varies by research site (from January 1, 2001 to January 1, 2010). Follow-up begins at insertion and ends at first occurrence of an outcome of interest, a censoring event (device removal or reinsertion, pregnancy, hysterectomy, sterilization, device expiration, death, disenrollment, last clinical encounter), or end of the study period (June 30, 2018). Comparisons of levels of exposure variables were made using Cox regression models with confounding adjusted by propensity score weighting using overlap weights. The study population includes 326,658 women with at least 1 device insertion during the study period (Kaiser Permanente Northern California, 161,442; Kaiser Permanente Southern California, 123,214; Kaiser Permanente Washington, 20,526; Regenstrief Institute, 21,476). The median duration of continuous enrollment was 90 (site medians 74-177) months. The mean age was 32 years, and the population was racially and ethnically diverse across the 4 sites. The mean body mass index was 28.5 kg/m2, and of the women included in the study, 10.0% had menorrhagia ≤12 months before insertion, 5.3% had uterine fibroids, and 10% were recent smokers; furthermore, among these women, 79.4% had levonorgestrel-releasing devices, and 19.5% had copper devices. Across sites, 97,824 women had an intrauterine device insertion at ≤52 weeks after delivery, of which 94,817 women (97%) had breastfeeding status at insertion determined; in addition, 228,834 women had intrauterine device insertion at >52 weeks after delivery or no evidence of a delivery in their health record. Combining retrospective data from multiple sites allowed for a large and diverse study population. Collaboration with clinicians in the study design and validation of outcomes ensured that the APEX-IUD study results reflect current United States clinical practice. Results from this study will provide valuable information based on real-world evidence about risk factors for intrauterine devices perforation and expulsion for clinicians. Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.

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