{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T03:22:05Z","timestamp":1772767325450,"version":"3.50.1"},"reference-count":69,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2007,1,31]],"date-time":"2007-01-31T00:00:00Z","timestamp":1170201600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Prenatal Diagnosis"],"published-print":{"date-parts":[[2007,4]]},"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 screening markers, namely, fetal nuchal translucency (NT), maternal serum free \u03b2\u2010human chorionic gonadotrophin (\u03b2\u2010hCG) and pregnancy\u2010associated plasma protein\u2010A (PAPP\u2010A), at 10 to 13<jats:sup>+6<\/jats:sup> weeks of gestation in Saudi women and to evaluate the effect of co\u2010variables including maternal body weight, gravidity, parity, fetal gender, twin pregnancy, smoking and ethnicity on these markers.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>A cohort of Saudi women (first cohort <jats:italic>n<\/jats:italic> = 1616) with singleton pregnancies prospectively participated in the present study, and fetal NT together with maternal serum free \u03b2\u2010hCG and PAPP\u2010A were determined at 10 to 13<jats:sup>+6<\/jats:sup> weeks of gestation. The distribution of gestational age\u2010independent multiples of the median (MoM) of the parameters was defined and normative values were established, and correction for maternal body weight was made accordingly. The influence of various co\u2010variables was examined using the data collected from the first and the second (<jats:italic>n<\/jats:italic> = 1849) cohorts of women and 62 twin pregnancies, and compared with other studies.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>All markers exhibited log\u2010normally distributed MoMs. Gestational age\u2010independent normative values were established. Maternal body weight was corrected, particularly for maternal free \u03b2\u2010hCG and PAPP\u2010A using standard methods. Fetal NT showed a negative relationship with increasing gravidity (<jats:italic>r<\/jats:italic> = \u22120.296) or parity (<jats:italic>r<\/jats:italic> = \u22120.311), whereas both free \u03b2\u2010hCG and PAPP\u2010A exhibited a significant positive relationship. There was a significant increase in the MoM of free \u03b2\u2010hCG in female fetuses. Smoking decreased MoM values of free \u03b2\u2010hCG (by 14.6%; <jats:italic>P<\/jats:italic> &lt; 0.01) and PAPP\u2010A (by 18.8%; <jats:italic>P<\/jats:italic> &lt; 0.001). Twin pregnancy showed significant increases in MoM values of free \u03b2\u2010hCG (by 1.87\u2010fold) and PAPP\u2010A (by 2.24\u2010fold), with no significant changes in fetal NT MoM values. Fetal NT MoM values were lower in Africans and Asians but higher in Orientals, as compared to Saudi women (<jats:italic>P<\/jats:italic> &lt; 0.05; in each case). MoM values (body weight\u2010corrected) of free \u03b2\u2010hCG were 25.2% higher in Africans and 19.4% higher in Orientals but 6.8% lower in other Arabian and Asian (by 5.8%) women as compared to Saudi women (<jats:italic>P<\/jats:italic> &lt; 0.05; in each case).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>The normative values and distribution parameters for fetal NT, maternal serum free \u03b2\u2010hCG and PAPP\u2010A were established in Saudi singleton pregnancies, the maternal body weight together with smoking, twin pregnancy and ethnicity being important first\u2010trimester screening co\u2010variables. Gravidity, parity and fetal gender are also considered to influence one or more of the first\u2010trimester markers examined. Copyright \u00a9 2007 John Wiley &amp; Sons, Ltd.<\/jats:p><\/jats:sec>","DOI":"10.1002\/pd.1661","type":"journal-article","created":{"date-parts":[[2007,2,3]],"date-time":"2007-02-03T05:42:07Z","timestamp":1170481327000},"page":"303-311","source":"Crossref","is-referenced-by-count":18,"title":["Maternal serum free\u2010\u03b2\u2010chorionic gonadotrophin, pregnancy\u2010associated plasma protein\u2010A and fetal nuchal translucency thickness at 10\u201313<sup>+6<\/sup> weeks in relation to co\u2010variables in pregnant Saudi women"],"prefix":"10.1002","volume":"27","author":[{"given":"Mohammed\u2010Salleh M.","family":"Ardawi","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hasan A.","family":"Nasrat","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Abdulrahim A.","family":"Rouzi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohammed H.","family":"Qari","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohammed H.","family":"Al\u2010Qahtani","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adel M.","family":"Abuzenadah","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2007,1,31]]},"reference":[{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1046\/j.1469-0705.2002.00808.x"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/pd.363"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.1136\/jms.8.2.61"},{"key":"e_1_2_1_5_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1471-0528.2002.01394.x"},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0223(199904)19:4<360::AID-PD556>3.0.CO;2-U"},{"key":"e_1_2_1_7_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0223(200003)20:3<186::AID-PD776>3.0.CO;2-A"},{"key":"e_1_2_1_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0344-0338(11)80744-2"},{"key":"e_1_2_1_9_1","doi-asserted-by":"publisher","DOI":"10.1369\/jhc.4B6420.2005"},{"key":"e_1_2_1_10_1","doi-asserted-by":"publisher","DOI":"10.1080\/147222405000104906"},{"key":"e_1_2_1_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/pd.1304"},{"key":"e_1_2_1_12_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0223(199606)16:6<503::AID-PD902>3.0.CO;2-F"},{"key":"e_1_2_1_13_1","doi-asserted-by":"publisher","DOI":"10.1002\/pd.1445"},{"key":"e_1_2_1_14_1","first-page":"645","article-title":"The 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