{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T02:02:28Z","timestamp":1775181748152,"version":"3.50.1"},"reference-count":31,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2009,3,23]],"date-time":"2009-03-23T00:00:00Z","timestamp":1237766400000},"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":["Ultrasound in Obstet &amp;amp; Gyne"],"published-print":{"date-parts":[[2009,4]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Objective<\/jats:title><jats:p>To establish normative values and distribution parameters of first\u2010trimester maternal serum free \u03b2\u2010human chorionic gonadotropin (\u03b2\u2010hCG), pregnancy\u2010associated plasma protein\u2010A (PAPP\u2010A) and fetal nuchal translucency (NT) thickness in Chinese women and to examine the effects of covariates on their levels.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Maternal serum free \u03b2\u2010hCG, PAPP\u2010A and fetal NT were measured in 9762 women presenting for first\u2010trimester combined screening for Down syndrome at 11 to 14 weeks of gestation. Individuals' markers were converted to multiples of the median (MoM) using expected medians estimated by performing a weighted regression analysis. Multivariate regression analysis was performed to assess the influence of maternal weight, parity, ethnicity, chorionicity in twin pregnancies, smoking, insulin\u2010dependent diabetes and mode of conception on individual marker MoM levels.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Both free \u03b2\u2010hCG and PAPP\u2010A median values demonstrated an exponential relationship with gestational age in days. Multivariate regression analysis indicated that free \u03b2\u2010hCG MoM was statistically significantly dependent on maternal weight (<jats:italic>P<\/jats:italic> &lt; 0.0001) and chorionicity in twin pregnancy (both monochorionic and dichorionic <jats:italic>P<\/jats:italic> &lt; 0.0001), that PAPP\u2010A MoM was dependent on maternal weight (<jats:italic>P<\/jats:italic> &lt; 0.0001), parity (<jats:italic>P<\/jats:italic> &lt; 0.0001), chorionicity in twin pregnancy (both monochorionic and dichorionic <jats:italic>P<\/jats:italic> &lt; 0.0001) and mode of conception (<jats:italic>P<\/jats:italic> = 0.002), and that fetal NT\u2010MoM was dependent on maternal weight (<jats:italic>P<\/jats:italic> = 0.0006) and mode of conception (<jats:italic>P<\/jats:italic> = 0.012).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Normative values have been generated to allow conversion of NT, free \u03b2\u2010hCG and PAPP\u2010A to their MoM equivalents and correction factors have been determined to adjust for maternal and pregnancy characteristics for use in ethnic Chinese women undergoing first\u2010trimester screening for aneuploidy. Copyright \u00a9 2009 ISUOG. Published by John Wiley &amp; Sons, Ltd.<\/jats:p><\/jats:sec>","DOI":"10.1002\/uog.6340","type":"journal-article","created":{"date-parts":[[2009,3,23]],"date-time":"2009-03-23T09:06:21Z","timestamp":1237799181000},"page":"387-393","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["Medians and correction factors for biochemical and ultrasound markers in Chinese women undergoing first\u2010trimester screening for trisomy 21"],"prefix":"10.1002","volume":"33","author":[{"given":"D. S.","family":"Sahota","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"T. Y.","family":"Leung","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"T. Y.","family":"Fung","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"L. 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