{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T22:40:45Z","timestamp":1783464045037,"version":"3.55.0"},"reference-count":27,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2013,9,10]],"date-time":"2013-09-10T00:00:00Z","timestamp":1378771200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["BJOG"],"published-print":{"date-parts":[[2014,1]]},"abstract":"<jats:sec><jats:title>Objective<\/jats:title><jats:p>To study whether pregnancy week at delivery is an independent risk factor for shoulder dystocia.<\/jats:p><\/jats:sec><jats:sec><jats:title>Design<\/jats:title><jats:p>Population study.<\/jats:p><\/jats:sec><jats:sec><jats:title>Setting<\/jats:title><jats:p>Medical Birth Registry of Norway.<\/jats:p><\/jats:sec><jats:sec><jats:title>Population<\/jats:title><jats:p>All vaginal deliveries of singleton offspring in cephalic presentation in Norway during 1967 through 2009 (<jats:italic>n<\/jats:italic>\u00a0=\u00a02\u00a0014\u00a0956).<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>The incidence of shoulder dystocia was calculated according to pregnancy week at delivery. The associations of pregnancy week at delivery with shoulder dystocia were estimated as crude and adjusted odds ratios using logistic regression analyses. We repeated the analyses in pregnancies with and without maternal diabetes.<\/jats:p><\/jats:sec><jats:sec><jats:title>Main outcome measures<\/jats:title><jats:p>Shoulder dystocia at delivery.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The overall incidence of shoulder dystocia was 0.73% (<jats:italic>n<\/jats:italic>\u00a0=\u00a014\u00a0820), and the incidence increased by increasing pregnancy week at delivery. Birthweight was strongly associated with shoulder dystocia. After adjustment for birthweight, induction of labour, use of epidural analgesia at delivery, prolonged labour, forceps\u2010assisted and vacuum\u2010assisted delivery, parity, period of delivery and maternal age in multivariable analyses, the adjusted odds ratios for shoulder dystocia were 1.77 (1.42\u20132.20) for deliveries at 32\u201335\u00a0weeks of gestation, and 0.84 (0.79\u20130.88) at 42\u201343\u00a0weeks of gestation, using weeks 40\u201341 as the reference. In pregnancies affected by diabetes (<jats:italic>n<\/jats:italic>\u00a0=\u00a011\u00a0188), the incidence of shoulder dystocia was 3.95%, and after adjustment for birthweight the adjusted odds ratio for shoulder dystocia was 2.92 (95% <jats:styled-content style=\"fixed-case\">CI<\/jats:styled-content> 1.54\u20135.52) for deliveries at weeks 32\u201335 of gestation, and 0.91 (95% <jats:styled-content style=\"fixed-case\">CI<\/jats:styled-content> 0.50\u20131.66) at 42\u201343\u00a0weeks of gestation.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>The risk of shoulder dystocia was associated with increased birthweight, diabetes, induction of labour, use of epidural analgesia at delivery, prolonged labour, forceps\u2010assisted and vacuum\u2010assisted delivery, parity and period of delivery but not with post\u2010term delivery.<\/jats:p><\/jats:sec>","DOI":"10.1111\/1471-0528.12427","type":"journal-article","created":{"date-parts":[[2013,9,11]],"date-time":"2013-09-11T09:15:55Z","timestamp":1378890955000},"page":"34-42","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":46,"title":["Pregnancy week at delivery and the risk of shoulder dystocia: a population study of 2\u00a0014\u00a0956 deliveries"],"prefix":"10.1111","volume":"121","author":[{"given":"EA","family":"\u00d8verland","sequence":"first","affiliation":[{"name":"Department of Obstetrics and Gynecology Akershus University Hospital and Institute of Clinical Medicine University of Oslo Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"LJ","family":"Vatten","sequence":"additional","affiliation":[{"name":"Department of Public Health Medical Faculty Norwegian University of Science and Technology Trondheim Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A","family":"Eskild","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology Akershus University Hospital and Institute of Clinical Medicine University of Oslo Oslo Norway"},{"name":"Division of Mental Health Norwegian Institute of Public Health Oslo Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2013,9,10]]},"reference":[{"key":"e_1_2_11_2_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471-0528.2010.02834.x"},{"key":"e_1_2_11_3_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471-0528.1998.tb10003.x"},{"key":"e_1_2_11_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.bpobgyn.2009.01.002"},{"key":"e_1_2_11_5_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajog.2005.09.007"},{"key":"e_1_2_11_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ogc.2011.02.015"},{"key":"e_1_2_11_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0020-7292(02)90001-9"},{"key":"e_1_2_11_8_1","doi-asserted-by":"publisher","DOI":"10.1097\/00003081-200006000-00005"},{"key":"e_1_2_11_9_1","doi-asserted-by":"publisher","DOI":"10.3109\/00016348909087691"},{"key":"e_1_2_11_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajog.2010.12.036"},{"key":"e_1_2_11_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0412.2011.01354.x"},{"key":"e_1_2_11_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajog.2008.12.038"},{"key":"e_1_2_11_13_1","doi-asserted-by":"publisher","DOI":"10.1097\/OGX.0b013e3181cb8fbc"},{"key":"e_1_2_11_14_1","first-page":"762","article-title":"Risk factors for shoulder dystocia","volume":"66","author":"Acker DB","year":"1985","journal-title":"Obstet Gynecol"},{"key":"e_1_2_11_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9378(82)90619-6"},{"key":"e_1_2_11_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/0029-7844(95)00099-D"},{"key":"e_1_2_11_17_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0029-7844(97)00049-5"},{"key":"e_1_2_11_18_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1464-5491.2010.02978.x"},{"key":"e_1_2_11_19_1","doi-asserted-by":"publisher","DOI":"10.1159\/000049410"},{"key":"e_1_2_11_20_1","doi-asserted-by":"publisher","DOI":"10.1034\/j.1600-0412.2000.079006435.x"},{"key":"e_1_2_11_21_1","doi-asserted-by":"publisher","DOI":"10.1038\/sj.ijo.0803178"},{"key":"e_1_2_11_22_1","doi-asserted-by":"publisher","DOI":"10.1186\/1471-2458-13-37"},{"key":"e_1_2_11_23_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMra061360"},{"key":"e_1_2_11_24_1","doi-asserted-by":"publisher","DOI":"10.1159\/000061025"},{"key":"e_1_2_11_25_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1520-6661(199811\/12)7:6<292::AID-MFM7>3.0.CO;2-A"},{"key":"e_1_2_11_26_1","doi-asserted-by":"publisher","DOI":"10.1097\/ALN.0b013e31817302e0"},{"key":"e_1_2_11_27_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0301-2115(03)00155-6"},{"key":"e_1_2_11_28_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1479-828X.2004.00301.x"}],"container-title":["BJOG: An International Journal of Obstetrics &amp; 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