{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T17:32:46Z","timestamp":1780075966681,"version":"3.54.0"},"reference-count":23,"publisher":"Wiley","issue":"7","license":[{"start":{"date-parts":[[2019,3,14]],"date-time":"2019-03-14T00:00:00Z","timestamp":1552521600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/501100004047","name":"Karolinska Institutet","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004047","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Acta Obstet Gynecol Scand"],"published-print":{"date-parts":[[2019,7]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Introduction<\/jats:title><jats:p>The objective was to investigate the Pearl index for ectopic pregnancy in women using the levonorgestrel intrauterine system (<jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content>) at the time of conception.<\/jats:p><\/jats:sec><jats:sec><jats:title>Material and methods<\/jats:title><jats:p>This was a substudy of a hospital\u2010based historical cohort including women with an ectopic pregnancy diagnosed in 4 referral hospitals in Stockholm, Sweden between December 2013 and April 2017. Study participants and type of contraception at time of conception were identified through the electronic medical chart system. Cases were defined as women with <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> 13.5 or 52\u00a0mg in situ at the time of diagnosis of ectopic pregnancy who had their <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> inserted 1 January 2014 or later. Outcome was defined as the incidence rate for ectopic pregnancy during use per 100 woman\u2010years (Pearl index) with 95% confidence interval (95% CI).<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The study includes 35 cases with <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> 13.5\u00a0mg and 13 cases with <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> 52\u00a0mg, which occurred in 18\u00a0488 (13.5\u00a0mg) and 50\u00a0246 (52\u00a0mg) exposed woman\u2010years. Pearl index for ectopic pregnancy was estimated at 0.19 (95% <jats:styled-content style=\"fixed-case\">CI<\/jats:styled-content> 0.15\u20100.28) for <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> 13.5\u00a0mg and to 0.006 (95% <jats:styled-content style=\"fixed-case\">CI<\/jats:styled-content> 0.00\u20100.01) for <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> 52\u00a0mg. The most cases for the <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> 13.5\u00a0mg (n\u00a0=\u00a026; 74%) occurred during the first year of use with a corresponding Pearl index at 0.23 (95% <jats:styled-content style=\"fixed-case\">CI<\/jats:styled-content> 0.14\u20100.35).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The absolute risk of ectopic pregnancy during the use of <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content> remains low. Our method may underestimate as well as overestimate the Pearl index for ectopic pregnancy. The findings underline the importance of identifying risk factors for ectopic pregnancy at insertion, and to rule out ectopic pregnancy for all women presenting with abdominal discomfort during the use of <jats:styled-content style=\"fixed-case\">LNG<\/jats:styled-content>\u2010<jats:styled-content style=\"fixed-case\">IUS<\/jats:styled-content>. Longer observation periods and prospective studies in a general population are a priority for further research.<\/jats:p><\/jats:sec>","DOI":"10.1111\/aogs.13564","type":"journal-article","created":{"date-parts":[[2019,2,9]],"date-time":"2019-02-09T02:19:30Z","timestamp":1549678770000},"page":"937-943","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Levonorgestrel intrauterine contraceptive systems (13.5\u00a0mg and 52\u00a0mg) and risk of ectopic pregnancy"],"prefix":"10.1111","volume":"98","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1355-9973","authenticated-orcid":false,"given":"Sofie","family":"Graner","sequence":"first","affiliation":[{"name":"Department of Medicine Center for Pharmacoepidemiology Karolinska Institutet Karolinska University Hospital Stockholm Sweden"},{"name":"Maternity BB Stockholm Danderyds Hospital Stockholm 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