{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,24]],"date-time":"2026-08-24T14:33:38Z","timestamp":1787582018796,"version":"build-2736575974"},"reference-count":14,"publisher":"Elsevier BV","issue":"3","license":[{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/legal\/tdmrep-license"},{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-017"},{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-037"},{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-012"},{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-029"},{"start":{"date-parts":[[2013,9,1]],"date-time":"2013-09-01T00:00:00Z","timestamp":1377993600000},"content-version":"stm-asf","delay-in-days":0,"URL":"https:\/\/doi.org\/10.15223\/policy-004"}],"funder":[{"DOI":"10.13039\/100008523","name":"Center for Clinical and Translational Science, University of Illinois at Chicago","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100008523","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["HHSN267200603425C"],"award-info":[{"award-number":["HHSN267200603425C"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100009633","name":"Eunice Kennedy Shriver National Institute of Child Health and Human Development","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100009633","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000097","name":"National Center for Research Resources","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000097","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100010573","name":"Center for Clinical and Translational Science, University of Utah","doi-asserted-by":"publisher","award":["UL1RR029879"],"award-info":[{"award-number":["UL1RR029879"]}],"id":[{"id":"10.13039\/100010573","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100008522","name":"University of Illinois at Chicago","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100008522","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["clinicalkey.fr","clinicalkey.jp","clinicalkey.com.au","clinicalkey.es","ajog.org","clinicalkey.com","elsevier.com","sciencedirect.com"],"crossmark-restriction":true},"short-container-title":["American Journal of Obstetrics and Gynecology"],"published-print":{"date-parts":[[2013,9]]},"DOI":"10.1016\/j.ajog.2013.06.019","type":"journal-article","created":{"date-parts":[[2013,7,17]],"date-time":"2013-07-17T04:30:23Z","timestamp":1374035423000},"page":"254.e1-254.e5","update-policy":"https:\/\/doi.org\/10.1016\/elsevier_cm_policy","source":"Crossref","is-referenced-by-count":14,"title":["Labor patterns in twin gestations"],"prefix":"10.1016","volume":"209","author":[{"given":"Heidi K.","family":"Leftwich","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mary N.","family":"Zaki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isabelle","family":"Wilkins","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Judith U.","family":"Hibbard","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"78","reference":[{"key":"10.1016\/j.ajog.2013.06.019_bib1","first-page":"1","article-title":"Births: final data for 2002","volume":"52","author":"Martin","year":"2003","journal-title":"Natl Vital Stat Rep"},{"key":"10.1016\/j.ajog.2013.06.019_bib2","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1016\/0029-7844(94)00354-G","article-title":"Increasing trends in plural birth in the United States","volume":"85","author":"Jewell","year":"1995","journal-title":"Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib3","doi-asserted-by":"crossref","first-page":"1095","DOI":"10.1097\/AOG.0b013e3182318651","article-title":"Trends in cesarean delivery for twin births in the United States","volume":"118","author":"Lee","year":"2001","journal-title":"Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib4","series-title":"Labor: clinical evaluation and management","first-page":"30","author":"Friedman","year":"1978"},{"key":"10.1016\/j.ajog.2013.06.019_bib5","doi-asserted-by":"crossref","first-page":"1568","DOI":"10.1016\/0002-9378(54)90311-7","article-title":"The graphic analysis of labor","volume":"68","author":"Friedman","year":"1954","journal-title":"Am J Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib6","doi-asserted-by":"crossref","first-page":"1281","DOI":"10.1097\/AOG.0b013e3181fdef6e","article-title":"Contemporary patterns of spontaneous labor with normal neonatal outcomes","volume":"116","author":"Zhang","year":"2009","journal-title":"Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib7","first-page":"46","article-title":"Epidural analgesia lengthens the Friedman active phase of labor","volume":"100","author":"Alexander","year":"2002","journal-title":"Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib8","doi-asserted-by":"crossref","first-page":"326.e1","DOI":"10.1016\/j.ajog.2010.06.058","article-title":"Contemporary cesarean delivery practice in the United States","volume":"203","author":"Zhang","year":"2010","journal-title":"Am J Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib9","doi-asserted-by":"crossref","first-page":"244.e1","DOI":"10.1016\/j.ajog.2011.06.014","article-title":"Contemporary labor patterns: the impact of maternal body mass index","volume":"205","author":"Kominiarek","year":"2011","journal-title":"Am J Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib10","doi-asserted-by":"crossref","first-page":"419.e1","DOI":"10.1016\/j.ajog.2012.03.003","article-title":"Changes in labor patterns over 50 years","volume":"206","author":"Laughon","year":"2012","journal-title":"Am J Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib11","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/S1071-5576(00)00067-8","article-title":"Comparison of active phase labor between triplet, twin, and singleton gestations","volume":"7","author":"Silver","year":"2000","journal-title":"J\u00a0Soc Gynecol Investig"},{"key":"10.1016\/j.ajog.2013.06.019_bib12","first-page":"164","article-title":"The effect of uterine over distention on labor","volume":"23","author":"Friedman","year":"1964","journal-title":"Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib13","doi-asserted-by":"crossref","first-page":"1181","DOI":"10.1016\/S0002-9378(98)70128-0","article-title":"Progression of labor in twin versus singleton gestations","volume":"179","author":"Schiff","year":"1998","journal-title":"Am J Obstet Gynecol"},{"key":"10.1016\/j.ajog.2013.06.019_bib14","doi-asserted-by":"crossref","first-page":"386","DOI":"10.1097\/00003081-196006000-00011","article-title":"Physiology of the uterine contraction","volume":"3","author":"Caldeyro-Barcia","year":"1960","journal-title":"Clinical Obstet Gynecol"}],"container-title":["American Journal of Obstetrics and Gynecology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0002937813006273?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0002937813006273?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2024,5,17]],"date-time":"2024-05-17T11:45:33Z","timestamp":1715946333000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0002937813006273"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2013,9]]},"references-count":14,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2013,9]]}},"alternative-id":["S0002937813006273"],"URL":"https:\/\/doi.org\/10.1016\/j.ajog.2013.06.019","relation":{},"ISSN":["0002-9378"],"issn-type":[{"value":"0002-9378","type":"print"}],"subject":[],"published":{"date-parts":[[2013,9]]},"assertion":[{"value":"Elsevier","name":"publisher","label":"This article is maintained by"},{"value":"Labor patterns in twin gestations","name":"articletitle","label":"Article Title"},{"value":"American Journal of Obstetrics and Gynecology","name":"journaltitle","label":"Journal Title"},{"value":"https:\/\/doi.org\/10.1016\/j.ajog.2013.06.019","name":"articlelink","label":"CrossRef DOI link to publisher maintained version"},{"value":"article","name":"content_type","label":"Content Type"},{"value":"Copyright \u00a9 2013 Mosby, Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.","name":"copyright","label":"Copyright"}]}}