{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T16:27:11Z","timestamp":1790699231862,"version":"4.1.0"},"reference-count":31,"publisher":"Oxford University Press (OUP)","issue":"6","license":[{"start":{"date-parts":[[2021,7,1]],"date-time":"2021-07-01T00:00:00Z","timestamp":1625097600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006636","name":"Swedish Research Council for Health, Working life and Welfare","doi-asserted-by":"publisher","award":["2016\u201300748"],"award-info":[{"award-number":["2016\u201300748"]}],"id":[{"id":"10.13039\/501100006636","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2022,1,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Background<\/jats:title>\n                  <jats:p>Previous studies of preterm birth (PTB) concerning night work have been inconclusive and partly limited by imprecise data on working schedules. This study investigated the risk of PTB in relation to detailed, registry-based data on working hours.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>In a register-based prospective cohort study, we identified 4970 singleton births with information on PTB from the Swedish Medical Birth Register of health care employees in Stockholm. Day-by-day information on working hours 2008\u201316 was obtained from a computerized employee register. Odds ratios (ORs) of PTB according to work hour characteristics were analysed by logistic regression adjusted for mother\u2019s age, stature, body mass index (BMI), parity, smoking habits, education, profession and country of birth.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>There was an increased risk of PTB among those who frequently worked night shifts (&amp;gt;25 times) [OR, 1.62; 95% confidence interval (CI), 1.03\u20132.53] and who ever worked \u22653 consecutive night shifts (OR, 1.43; 95% CI, 1.03\u20131.99) during the first trimester. Frequently (&amp;gt; 8 times) working 3 or more consecutive nights, and frequently (&amp;gt;18 times) having quick returns from night shifts (&amp;lt;28\u2009h) during the first trimester showed 3\u20134 fold increased risk of PTB. Moreover, working frequent (&amp;gt;20 times) long shifts (\u226510\u2009h) (OR 1.63; 95% CI, 1.07\u20132.49) during the first trimester and working any Week &amp;gt;40\u2009h (OR 2.05; 95% CI, 1.31\u20133.22) during the third trimester were associated with PTB.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>In this cohort of Swedish health care employees with registry-based data on working hours, night work, especially working frequent consecutive nights, and quick returns from night shifts during the first trimester were associated with increased risk of PTB among pregnant women.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/ije\/dyab135","type":"journal-article","created":{"date-parts":[[2021,6,11]],"date-time":"2021-06-11T11:20:59Z","timestamp":1623410459000},"page":"1864-1874","source":"Crossref","is-referenced-by-count":49,"title":["Shift and night work during pregnancy and preterm birth\u2014a cohort study of Swedish health care employees"],"prefix":"10.1093","volume":"50","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8181-648X","authenticated-orcid":false,"given":"Manzur","family":"Kader","sequence":"first","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carolina","family":"Bigert","sequence":"additional","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"},{"name":"Centre for Occupational and Environmental Medicine, Region Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tomas","family":"Andersson","sequence":"additional","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"},{"name":"Centre for Occupational and Environmental Medicine, Region Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jenny","family":"Selander","sequence":"additional","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2074-5857","authenticated-orcid":false,"given":"Theo","family":"Bodin","sequence":"additional","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"},{"name":"Centre for Occupational and Environmental Medicine, Region Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helena","family":"Skr\u00f6der","sequence":"additional","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mikko","family":"H\u00e4rm\u00e4","sequence":"additional","affiliation":[{"name":"Finnish Institute of Occupational Health, Helsinki, Finland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Albin","sequence":"additional","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"},{"name":"Centre for Occupational and Environmental Medicine, Region Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Per","family":"Gustavsson","sequence":"additional","affiliation":[{"name":"Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden"},{"name":"Centre for Occupational and Environmental Medicine, Region Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2021,7,1]]},"reference":[{"key":"2022010923052121000_dyab135-B1","year":"2017"},{"key":"2022010923052121000_dyab135-B2","doi-asserted-by":"crossref","first-page":"75","DOI":"10.7861\/clinmedicine.13-1-75","article-title":"Pregnancy: occupational aspects of management: concise guidance","volume":"13","author":"Palmer","year":"2013","journal-title":"Clin Med (Lond)"},{"key":"2022010923052121000_dyab135-B3","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1055\/s-0036-1571354","article-title":"Fixed or rotating night shift work undertaken by women: implications for fertility and miscarriage","volume":"34","author":"Fernandez","year":"2016","journal-title":"Semin Reprod Med"},{"key":"2022010923052121000_dyab135-B4","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.bpobgyn.2018.04.003","article-title":"The global epidemiology of preterm birth","volume":"52","author":"Vogel","year":"2018","journal-title":"Best Pract Res Clin Obstet Gynaecol"},{"key":"2022010923052121000_dyab135-B5","doi-asserted-by":"crossref","first-page":"228","DOI":"10.1136\/oem.2006.026872","article-title":"Risk of prematurity, low birthweight and pre-eclampsia in relation to working hours and physical activities: a systematic review","volume":"64","author":"Bonzini","year":"2007","journal-title":"Occup Environ Med"},{"key":"2022010923052121000_dyab135-B6","doi-asserted-by":"crossref","first-page":"1429","DOI":"10.1111\/j.1471-0528.2011.03066.x","article-title":"Shift work and pregnancy outcomes: a systematic review with meta-analysis of currently available epidemiological studies","volume":"118","author":"Bonzini","year":"2011","journal-title":"BJOG"},{"key":"2022010923052121000_dyab135-B7","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1136\/oemed-2012-101032","article-title":"Work activities and risk of prematurity, low birthweight and pre-eclampsia: an updated review with meta-analysis","volume":"70","author":"Palmer","year":"2013","journal-title":"Occup Environ Med"},{"key":"2022010923052121000_dyab135-B8","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1007\/s00420-014-0934-9","article-title":"Shift work, long working hours and preterm birth: a systematic review and meta-analysis","volume":"87","author":"van Melick","year":"2014","journal-title":"Int Arch Occup Environ Health"},{"key":"2022010923052121000_dyab135-B9","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1016\/j.ajog.2019.06.051","article-title":"The impact of occupational shift work and working hours during pregnancy on health outcomes: a systematic review and meta-analysis","volume":"221","author":"Cai","year":"2019","journal-title":"Am J Obstet Gynecol"},{"key":"2022010923052121000_dyab135-B10","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1177\/193672441100500105","article-title":"Implications of using different measures of work shift in survey research","volume":"5","author":"Ward","year":"2011","journal-title":"J Appl Soc Sci"},{"key":"2022010923052121000_dyab135-B11","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1136\/oem.2009.053512","article-title":"Considerations of circadian impact for defining \u2018shift work\u2019 in cancer studies: IARC Working Group Report","volume":"68","author":"Stevens","year":"2011","journal-title":"Occup Environ Med"},{"key":"2022010923052121000_dyab135-B12","doi-asserted-by":"crossref","first-page":"e0215748","DOI":"10.1371\/journal.pone.0215748","article-title":"Night work during pregnancy and preterm birth - a large register-based cohort study","volume":"14","author":"Specht","year":"2019","journal-title":"PLoS One"},{"key":"2022010923052121000_dyab135-B13","doi-asserted-by":"crossref","first-page":"268","DOI":"10.5271\/sjweh.3492","article-title":"Developing register-based measures for assessment of working time patterns for epidemiologic studies","volume":"41","author":"Harma","year":"2015","journal-title":"Scand J Work Environ Health"},{"key":"2022010923052121000_dyab135-B14","year":"2014"},{"key":"2022010923052121000_dyab135-B15","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1177\/140349489001800209","article-title":"A quality study of a medical birth registry","volume":"18","author":"Cnattingius","year":"1990","journal-title":"Scand J Soc Med"},{"key":"2022010923052121000_dyab135-B16","year":"2015"},{"key":"2022010923052121000_dyab135-B17","doi-asserted-by":"crossref","first-page":"77","DOI":"10.4103\/0019-5278.55123","article-title":"Healthy worker effect phenomenon","volume":"13","author":"Shah","year":"2009","journal-title":"Indian J Occup Environ Med"},{"key":"2022010923052121000_dyab135-B18","doi-asserted-by":"crossref","first-page":"534","DOI":"10.1177\/0748730417728671","article-title":"Rhythmic three-part harmony: the complex interaction of maternal, placental and fetal circadian systems","volume":"32","author":"Mark","year":"2017","journal-title":"J Biol Rhythms"},{"key":"2022010923052121000_dyab135-B19","doi-asserted-by":"crossref","first-page":"1454","DOI":"10.3109\/07420528.2010.498067","article-title":"Working the night shift causes increased vascular stress and delayed recovery in young women","volume":"27","author":"Lo","year":"2010","journal-title":"Chronobiol Int"},{"key":"2022010923052121000_dyab135-B20","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1097\/AOG.0000000000002132","article-title":"Sleep disorder diagnosis during pregnancy and risk of preterm birth","volume":"130","author":"Felder","year":"2017","journal-title":"Obstet Gynecol"},{"key":"2022010923052121000_dyab135-B21","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1007\/s00420-015-1093-3","article-title":"The effect of the number of consecutive night shifts on diurnal rhythms in cortisol, melatonin and heart rate variability (HRV): a systematic review of field studies","volume":"89","author":"Jensen","year":"2016","journal-title":"Int Arch Occup Environ Health"},{"key":"2022010923052121000_dyab135-B22","doi-asserted-by":"crossref","first-page":"830","DOI":"10.1158\/1055-9965.EPI-15-1178","article-title":"Shift work, chronotype, and melatonin patterns among female hospital employees on day and night shifts","volume":"25","author":"Leung","year":"2016","journal-title":"Cancer Epidemiol Biomarkers Prev"},{"key":"2022010923052121000_dyab135-B23","doi-asserted-by":"crossref","first-page":"1231","DOI":"10.3109\/07420528.2014.957304","article-title":"Progressive decrease of melatonin production over consecutive days of simulated night work","volume":"31","author":"Dumont","year":"2014","journal-title":"Chronobiol Int"},{"key":"2022010923052121000_dyab135-B24","doi-asserted-by":"crossref","first-page":"1203","DOI":"10.1080\/07420520601100955","article-title":"Diurnal urinary 6-sulfatoxymelatonin levels among healthy Danish nurses during work and leisure time","volume":"23","author":"Marie Hansen","year":"2006","journal-title":"Chronobiol Int"},{"key":"2022010923052121000_dyab135-B25","doi-asserted-by":"crossref","first-page":"1193","DOI":"10.1016\/j.ijnurstu.2015.04.001","article-title":"Differences in cortisol profiles and circadian adjustment time between nurses working night shifts and regular day shifts: a prospective longitudinal study","volume":"52","author":"Niu","year":"2015","journal-title":"Int J Nurs Stud"},{"key":"2022010923052121000_dyab135-B26","doi-asserted-by":"crossref","first-page":"92","DOI":"10.3389\/fendo.2013.00092","article-title":"Shift work and circadian dysregulation of reproduction","volume":"4","author":"Gamble","year":"2013","journal-title":"Front Endocrinol (Lausanne)"},{"key":"2022010923052121000_dyab135-B27","doi-asserted-by":"crossref","first-page":"1014","DOI":"10.1093\/aje\/kwp218","article-title":"Maternal catecholamine levels in midpregnancy and risk of preterm delivery","volume":"170","author":"Holzman","year":"2009","journal-title":"Am J Epidemiol"},{"key":"2022010923052121000_dyab135-B28","year":"2013"},{"key":"2022010923052121000_dyab135-B29","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1016\/j.ajog.2019.08.059","article-title":"The impact of occupational activities during pregnancy on pregnancy outcomes: a systematic review and metaanalysis","volume":"222","author":"Cai","year":"2020","journal-title":"Am J Obstet Gynecol"},{"key":"2022010923052121000_dyab135-B30","doi-asserted-by":"crossref","first-page":"310","DOI":"10.1080\/00140139.2015.1058426","article-title":"Sleep and need for recovery in shift workers: do chronotype and age matter?","volume":"59","author":"van de Ven","year":"2016","journal-title":"Ergonomics"},{"key":"2022010923052121000_dyab135-B31","doi-asserted-by":"crossref","first-page":"557","DOI":"10.5271\/sjweh.3920","article-title":"How to schedule night shift work in order to reduce health and safety risks","volume":"46","author":"Garde","year":"2020","journal-title":"Scand J Work Environ Health"}],"container-title":["International Journal of Epidemiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/ije\/article-pdf\/50\/6\/1864\/42092240\/dyab135.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/ije\/article-pdf\/50\/6\/1864\/42092240\/dyab135.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T23:22:09Z","timestamp":1641770529000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/ije\/article\/50\/6\/1864\/6312005"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,7,1]]},"references-count":31,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2021,7,1]]},"published-print":{"date-parts":[[2022,1,6]]}},"URL":"https:\/\/doi.org\/10.1093\/ije\/dyab135","relation":{},"ISSN":["0300-5771","1464-3685"],"issn-type":[{"value":"0300-5771","type":"print"},{"value":"1464-3685","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2021,12,1]]},"published":{"date-parts":[[2021,7,1]]}}}