{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,24]],"date-time":"2026-10-24T02:13:12Z","timestamp":1792807992409,"version":"4.5.0"},"reference-count":20,"publisher":"BMJ","issue":"10","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2018,10,4]]},"published-print":{"date-parts":[[2018,10]]},"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To determine whether uterine distention is associated with human pregnancy duration in a non-invasive observational setting.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Retrospective cohort study modelling uterine distention by interaction between maternal height and uterine load.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>The study is based on the 1990\u20132013 population data from all delivery units in Sweden.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Participants<\/jats:title>\n                    <jats:p>Uncomplicated first pregnancies of healthy Nordic-born mothers with spontaneous onset of labour. Pregnancies were classified as twin (n=2846) or singleton (n=527\u2009868). Singleton pregnancies were further classified as carrying a large for gestational age fetus (LGA, n=24\u2009286) or small for gestational age fetus (SGA, n=33\u2009780).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Outcome measures<\/jats:title>\n                    <jats:p>Statistical interaction between maternal height and uterine load categories (twin vs singleton pregnancies, and LGA vs SGA singleton pregnancies), where the outcome is pregnancy duration.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>In all models, statistically significant interaction was found. Mothers carrying twins had 2.9 times larger positive linear effect of maternal height on gestational age than mothers carrying singletons (interaction p=5e\u221214). Similarly, the effect of maternal height was strongly modulated by the fetal growth rate in singleton pregnancies: the effect size of maternal height on gestational age in LGA pregnancies was 2.1 times larger than that in SGA pregnancies (interaction p&lt;1e\u221211). Preterm birth OR was 1.4 when the mother was short, and 2.8 when the fetus was extremely large for its gestational age; however, when both risk factors were present together, the OR for preterm birth was larger than expected, 10.2 (interaction p&lt;0.0005).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Across all classes, maternal height was significantly associated with child\u2019s gestational age at birth. Interestingly, in short-statured women with large uterine load (twins, LGA), spontaneous delivery occurred much earlier than expected. The interaction between maternal height, uterine load size and gestational age at birth strongly suggests the effect of uterine distention imposed by fetal growth on birth timing.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2018-022929","type":"journal-article","created":{"date-parts":[[2018,11,1]],"date-time":"2018-11-01T02:45:19Z","timestamp":1541040319000},"page":"e022929","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":24,"title":["Uterine distention as a factor in birth timing: retrospective nationwide cohort study in Sweden"],"prefix":"10.1136","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2450-732X","authenticated-orcid":false,"given":"Jonas","family":"Bacelis","sequence":"first","affiliation":[{"name":"Department of Obstetrics and Gynecology, Sahlgrenska University Hospital \u00d6stra, Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julius","family":"Juodakis","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristina M","family":"Adams Waldorf","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Sahlgrenska University Hospital \u00d6stra, Gothenburg, Sweden"},{"name":"Department of Obstetrics and Gynecology, University of Washington, Seattle, Washington, USA"},{"name":"Department of Global Health, University of Washington, Seattle, Washington, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Verena","family":"Sengpiel","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Sahlgrenska University Hospital \u00d6stra, Gothenburg, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Louis J","family":"Muglia","sequence":"additional","affiliation":[{"name":"Human Genetics Division, Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, Ohio, USA"},{"name":"Center for Prevention of Preterm Birth, Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, Ohio, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ge","family":"Zhang","sequence":"additional","affiliation":[{"name":"Human Genetics Division, Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, Ohio, USA"},{"name":"Center for Prevention of Preterm Birth, Cincinnati Children\u2019s Hospital Medical Center, Cincinnati, Ohio, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Jacobsson","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Sahlgrenska University Hospital \u00d6stra, Gothenburg, Sweden"},{"name":"Department of Genetics and Bioinformatics, Area of Health Data and Digitalisation, Norwegian Institute of Public Health, Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2018,10,31]]},"reference":[{"key":"2025121403412308000_8.10.e022929.1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(16)31593-8"},{"key":"2025121403412308000_8.10.e022929.2","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(12)60820-4"},{"key":"2025121403412308000_8.10.e022929.3","doi-asserted-by":"publisher","DOI":"10.1126\/science.1251816"},{"key":"2025121403412308000_8.10.e022929.4","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(08)60108-7"},{"key":"2025121403412308000_8.10.e022929.5","doi-asserted-by":"crossref","first-page":"388","DOI":"10.1111\/j.1479-828X.2009.01006.x","article-title":"Maternal height and length of gestation: does this impact on preterm labour in Asian women?","volume":"49","author":"Chan","year":"2009","journal-title":"Aust N Z J Obstet Gynaecol"},{"key":"2025121403412308000_8.10.e022929.6","doi-asserted-by":"crossref","first-page":"349.e1","DOI":"10.1016\/j.ajog.2013.05.052","article-title":"Effect of maternal height and weight on risk for preterm singleton and twin births resulting from IVF in the United States, 2008-2010","volume":"209","author":"Dickey","year":"2013","journal-title":"Am J Obstet Gynecol"},{"key":"2025121403412308000_8.10.e022929.7","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0154304","article-title":"Maternal height and preterm birth: a study on 192,432 Swedish Women","volume":"11","author":"Derraik","year":"2016","journal-title":"PLoS One"},{"key":"2025121403412308000_8.10.e022929.8","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1111\/ppe.12087","article-title":"Predicting risk of spontaneous preterm delivery in women with a singleton pregnancy","volume":"28","author":"Morken","year":"2014","journal-title":"Paediatr Perinat Epidemiol"},{"key":"2025121403412308000_8.10.e022929.9","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pmed.1001865"},{"key":"2025121403412308000_8.10.e022929.10","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajog.2015.08.028"},{"key":"2025121403412308000_8.10.e022929.11","doi-asserted-by":"publisher","DOI":"10.1111\/j.1651-2227.1996.tb14164.x"},{"key":"2025121403412308000_8.10.e022929.12","first-page":"661","article-title":"Decidual morphology and F prostaglandin in amniotic fluid in stretch-induced abortion","volume":"64","author":"Manabe","year":"1984","journal-title":"Obstet Gynecol"},{"key":"2025121403412308000_8.10.e022929.13","doi-asserted-by":"publisher","DOI":"10.1016\/0090-6980(83)90119-3"},{"key":"2025121403412308000_8.10.e022929.14","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1205282109"},{"key":"2025121403412308000_8.10.e022929.15","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.4.12.370"},{"key":"2025121403412308000_8.10.e022929.16","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2011.220699"},{"key":"2025121403412308000_8.10.e022929.17","doi-asserted-by":"publisher","DOI":"10.1093\/molehr\/gah112"},{"key":"2025121403412308000_8.10.e022929.18","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2004-1390"},{"key":"2025121403412308000_8.10.e022929.19","doi-asserted-by":"publisher","DOI":"10.1093\/molehr\/gah021"},{"key":"2025121403412308000_8.10.e022929.20","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2004-0277"}],"container-title":["BMJ Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bmjopen-2018-022929","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,14]],"date-time":"2025-12-14T11:41:27Z","timestamp":1765712487000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmjopen.bmj.com\/lookup\/doi\/10.1136\/bmjopen-2018-022929"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,10]]},"references-count":20,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2018,10,31]]},"published-print":{"date-parts":[[2018,10]]}},"alternative-id":["10.1136\/bmjopen-2018-022929"],"URL":"https:\/\/doi.org\/10.1136\/bmjopen-2018-022929","relation":{},"ISSN":["2044-6055","2044-6055"],"issn-type":[{"value":"2044-6055","type":"print"},{"value":"2044-6055","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,10]]}}}