{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T03:48:16Z","timestamp":1792036096104,"version":"4.4.0"},"reference-count":30,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2019,2,13]],"date-time":"2019-02-13T00:00:00Z","timestamp":1550016000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/501100003123","name":"Fetal Medicine Foundation","doi-asserted-by":"publisher","award":["Charity No: 1037116"],"award-info":[{"award-number":["Charity No: 1037116"]}],"id":[{"id":"10.13039\/501100003123","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Ultrasound in Obstet &amp;amp; Gyne"],"published-print":{"date-parts":[[2019,4]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To develop gestational age\u2010based reference ranges for the pulsatility index in the umbilical artery (UA\u2010PI) and fetal middle cerebral artery (MCA\u2010PI) and the cerebroplacental ratio (MCA\u2010PI\/UA\u2010PI), and to examine the maternal characteristics and medical history that affect these measurements.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      This was a cross\u2010sectional study of 72\u2009387 pregnancies undergoing routine ultrasound examination at 20\u2009+\u20090 to 22\u2009+\u20096\u2009weeks' gestation (\n                      <jats:italic>n<\/jats:italic>\n                      \u00a0=\u20093712), 31\u2009+\u20090 to 33\u2009+\u20096\u2009weeks (\n                      <jats:italic>n<\/jats:italic>\n                      \u00a0=\u200929\u2009035), 35\u2009+\u20090 to 36\u2009+\u20096\u2009weeks (\n                      <jats:italic>n<\/jats:italic>\n                      \u00a0=\u200937\u2009252) or 41\u2009+\u20090 to 41\u2009+\u20096\u2009weeks (\n                      <jats:italic>n<\/jats:italic>\n                      \u00a0=\u20092388). For the purpose of this study, we included data for only one of the second\u2010 or third\u2010trimester visits. The inclusion criteria were singleton pregnancy, dating by fetal crown\u2013rump length at 11\u2009+\u20090 to 13\u2009+\u20096\u2009weeks' gestation, live birth of a morphologically normal neonate and ultrasonographic measurements by sonographers who had received the Fetal Medicine Foundation Certificate of Competence in Doppler ultrasound. Since the objectives of the study were to establish reference ranges, rather than normal ranges, and to examine factors from maternal characteristics and medical history that affect these measurements, we included all pregnancies having routine ultrasound examinations, irrespective of whether the mother had a pre\u2010existing medical condition, such as diabetes mellitus, or a pregnancy complication, such as pre\u2010eclampsia or suspected fetal growth restriction. Median and SD models were fitted between UA\u2010PI, MCA\u2010PI and CPR and gestational age. Assessment of goodness of fit of the models was by inspection of quantile\u2010to\u2010quantile (Q\u2013Q) plots of\n                      <jats:italic>Z<\/jats:italic>\n                      \u2010scores calculated using the mean and SD models. The distributions of MCA\u2010PI, UA\u2010PI and CPR\n                      <jats:italic>Z<\/jats:italic>\n                      \u2010scores were examined in relation to maternal characteristics and medical history.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The relationship between the median and gestational age was linear for UA\u2010PI and cubic for MCA\u2010PI and CPR and the SD was log quadratic for all three. MCA\u2010PI and CPR increased with gestational age from 20\u2009weeks' gestation to reach a peak at around 32 and 34\u2009weeks, respectively, and decreased thereafter, whereas UA\u2010PI decreased linearly with gestational age from 20 to 42\u2009weeks. Compared to the general population, significant deviations in multiples of the median values of UA\u2010PI, MCA\u2010PI and CPR were observed in subgroups of maternal age, body mass index, racial origin, method of conception and parity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This study established new reference ranges for UA\u2010PI, MCA\u2010PI and CPR, according to gestational age, and reports maternal characteristics and medical history that affect these measurements. Copyright \u00a9 2018 ISUOG. Published by John Wiley &amp; Sons Ltd.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/uog.20157","type":"journal-article","created":{"date-parts":[[2018,10,24]],"date-time":"2018-10-24T06:44:31Z","timestamp":1540363471000},"page":"465-472","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":195,"title":["Fetal Medicine Foundation reference ranges for umbilical artery and middle cerebral artery pulsatility index and cerebroplacental ratio"],"prefix":"10.1002","volume":"53","author":[{"given":"A.","family":"Ciobanu","sequence":"first","affiliation":[{"name":"Harris Birthright Research Centre for Fetal Medicine King's College Hospital  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"Wright","sequence":"additional","affiliation":[{"name":"Institute of Health Research University of Exeter  Exeter UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5856-6072","authenticated-orcid":false,"given":"A.","family":"Syngelaki","sequence":"additional","affiliation":[{"name":"Harris Birthright Research Centre for Fetal Medicine King's College Hospital  London UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D.","family":"Wright","sequence":"additional","affiliation":[{"name":"Institute of Health Research University of Exeter  Exeter UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7265-5442","authenticated-orcid":false,"given":"R.","family":"Akolekar","sequence":"additional","affiliation":[{"name":"Fetal Medicine Unit Medway Maritime Hospital  Gillingham UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K. 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