{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,2,20]],"date-time":"2025-02-20T05:12:43Z","timestamp":1740028363974,"version":"3.37.3"},"reference-count":26,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2023,5,2]],"date-time":"2023-05-02T00:00:00Z","timestamp":1682985600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Intl J Gynecology &amp; Obste"],"published-print":{"date-parts":[[2023,10]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Objective<\/jats:title><jats:p>Twin pregnancies are associated with increased antepartum and intrapartum risks. Limited multiple embryo transfers are associated with decreased twin birth rates. We aimed to study the effect of 2009 Icelandic regulations on twin birth rates and examine obstetric intervention rates for twin births during the study period.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>The study included all births (<jats:italic>N<\/jats:italic>\u2009=\u200994\u2009028) in Iceland during 1997\u20132018. Twin birth rates and obstetric intervention rates were compared over birth year periods using modified Poisson regression adjusted for confounders.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>An observed decrease in the twin birth rate trend was most notable from 2006 until 2009. Twin birth decreased in 2009\u20132013 (prevalence ratio [PR] 0.74, 95% confidence interval [CI] 0.64\u20130.86) and in 2014\u20132018 (PR 0.74, 95% CI 0.64\u20130.86) compared with 1997\u20132002. This decrease was only evident for women aged 30+ years in stratified analysis. Induction of labor rates increased from 26% in 1997\u20132002 to 44% in 2014\u20132018 (adjusted rate ratio [ARR] 2.10, 95% CI 1.72\u20132.57) whereas elective cesarean section (ARR 0.80, 95% CI 0.59\u20131.07) and urgent cesarean section (ARR 0.79, 95% CI 0.63\u20131.00) rates appeared to decline.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Twin births decreased during the study period. International guidelines published before the Icelandic regulations may have affected twin birth rates in Iceland. Induction of labor rates for twins increased while cesarean section rates decreased.<\/jats:p><\/jats:sec>","DOI":"10.1002\/ijgo.14817","type":"journal-article","created":{"date-parts":[[2023,5,2]],"date-time":"2023-05-02T09:20:11Z","timestamp":1683019211000},"page":"226-233","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Twin birth rates and obstetric interventions in Iceland: A nationwide study from 1997 to 2018"],"prefix":"10.1002","volume":"163","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2255-0260","authenticated-orcid":false,"given":"Jamie","family":"Ontiveros","sequence":"first","affiliation":[{"name":"Centre of Public Health Sciences, Faculty of Medicine University of Iceland  Reykjav\u00edk Iceland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2989-7160","authenticated-orcid":false,"given":"J\u00f3hanna","family":"Gunnarsd\u00f3ttir","sequence":"additional","affiliation":[{"name":"Centre of Public Health Sciences, Faculty of Medicine University of Iceland  Reykjav\u00edk Iceland"},{"name":"Department of Obstetrics and Gynecology Landsp\u00edtali The National University Hospital of Iceland  Reykjav\u00edk Iceland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3678-4217","authenticated-orcid":false,"given":"Sigurbj\u00f6rg Anna","family":"Gu\u00f0nad\u00f3ttir","sequence":"additional","affiliation":[{"name":"Centre of Public Health Sciences, Faculty of Medicine University of Iceland  Reykjav\u00edk Iceland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7998-5433","authenticated-orcid":false,"given":"Thor","family":"Aspelund","sequence":"additional","affiliation":[{"name":"Centre of Public Health Sciences, Faculty of Medicine University of Iceland  Reykjav\u00edk Iceland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4931-7650","authenticated-orcid":false,"given":"Kristjana","family":"Einarsd\u00f3ttir","sequence":"additional","affiliation":[{"name":"Centre of Public Health Sciences, Faculty of Medicine University of Iceland  Reykjav\u00edk Iceland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2023,5,2]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1093\/humrep\/deab029"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1186\/s12884-015-0566-4"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.5772\/intechopen.80092"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1214939"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1186\/s12884-019-2498-x"},{"key":"e_1_2_10_7_1","first-page":"442","article-title":"Postpartum hemorrhage: prevention and treatment","volume":"95","author":"Evensen A","year":"2017","journal-title":"Am Fam Physician"},{"key":"e_1_2_10_8_1","unstructured":"Ministry of Health Iceland.Regulations on Assisted Reproduction: [Ministry of Health Iceland website].2009https:\/\/www.reglugerd.is\/reglugerdir\/eftir-raduneytum\/heilbrigdis\/nr\/10797(accessed April 26 2021)."},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/tog.12460"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1111\/birt.12353"},{"key":"e_1_2_10_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/birt.12564"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.1111\/birt.12467"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1097\/AOG.0000000000002853"},{"key":"e_1_2_10_14_1","doi-asserted-by":"publisher","DOI":"10.3238\/arztebl.2010.0663"},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1093\/humupd\/dmr026"},{"key":"e_1_2_10_16_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1728-4457.2015.00088.x"},{"key":"e_1_2_10_17_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0149252"},{"key":"e_1_2_10_18_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.f650"},{"key":"e_1_2_10_19_1","doi-asserted-by":"publisher","DOI":"10.1111\/ajo.12478"},{"key":"e_1_2_10_20_1","unstructured":"Directorate of Health Iceland. 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