{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T07:06:23Z","timestamp":1782889583065,"version":"3.54.5"},"reference-count":30,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T00:00:00Z","timestamp":1782777600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T00:00:00Z","timestamp":1782777600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["BJOG"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To assess the internal consistency of the Hadlock normal range for estimated fetal weight (EFW) and its clinical implications.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Methodological analysis and retrospective observational audit.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Tertiary maternity hospital in Oxford, UK.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Population<\/jats:title>\n                    <jats:p>Women with a non\u2010anomalous singleton pregnancy.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Reanalysis of the original Hadlock reference EFW chart using functional data analysis (FDA) and penalised functional regression (PFFR\u2010GAM), and systematic bias assessment across gestation. Retrospective EFW centile analysis in a population of pregnancies undergoing a growth scan between 35\u2009+\u20090 and 36\u2009+\u20096\u2009weeks, calculating the EFW centile using both the published reference chart (chart\u2010derived centile) and the reported regression equation (equation\u2010derived centile).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Outcome Measures<\/jats:title>\n                    <jats:p>Agreement between chart\u2010derived and equation\u2010derived centiles and the corresponding differences in classification of fetuses below the 3rd and 10th centiles.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      There is a statistically significant disparity between the chart\u2010derived and equation\u2010derived centiles, most pronounced in the 3rd and 10th centiles where clinical implications are critical. The 3rd and 10th chart\u2010derived centiles approximately correspond to the 1st and 6th equation\u2010derived centiles. Conversely, the equation\u2010derived 10th centile corresponds to the chart\u2010derived 17th centile. In a population of 21\u2009874 pregnancies undergoing a growth scan between 35\u2009+\u20090 and 36\u2009+\u20096\u2009weeks, the chart classified 4.2% as below the 10th centile, compared with 7.2% using the equation, with an absolute difference of 3.0% (95% CI 2.8%\u20133.3%; McNemar's test;\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001). Also, the chart classified 0.8% under the 3rd centile, compared with 2.3% using the equation, with an absolute difference of 1.5% (95% CI 1.3%\u20131.7%; McNemar's test;\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&lt;\u20090.001).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Systematic disparity exists between the published chart\u2010 and equation\u2010derived centiles in the original Hadlock growth reference. The equation\u2010derived centiles are closer to the expected nominal proportions of our population, whereas the chart\u2010derived centiles significantly underestimate the incidence of small for gestational age.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1111\/1471-0528.70296","type":"journal-article","created":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T05:30:06Z","timestamp":1782883806000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Internal Consistency of the Hadlock Estimated Fetal Weight Reference: Methodological Analysis"],"prefix":"10.1111","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2365-6769","authenticated-orcid":false,"given":"Theophilus K.","family":"Adu\u2010Bredu","sequence":"first","affiliation":[{"name":"Nuffield Department of Women's and Reproductive Health University of Oxford  Oxford UK"},{"name":"John Radcliffe Hospital Oxford University Hospitals NHS Trust  Oxford 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