{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,26]],"date-time":"2025-11-26T15:43:14Z","timestamp":1764171794249},"reference-count":11,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2004,5,21]],"date-time":"2004-05-21T00:00:00Z","timestamp":1085097600000},"content-version":"vor","delay-in-days":20,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Prenatal Diagnosis"],"published-print":{"date-parts":[[2004,5]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Objectives<\/jats:title><jats:p>It has been reported that, in prenatal screening programmes for Down syndrome, women who have false\u2010positive results in one pregnancy have an increased risk of a false\u2010positive result in a subsequent pregnancy. We examined the effect of this in the screening programme conducted from the Wolfson Institute of Preventive Medicine with a view to determining the magnitude of the effect, and to describe a method of avoiding the problem.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Six thousand four hundred and forty\u2010eight women were identified who had had two singleton pregnancies without Down syndrome in the screening programme based at the Wolfson Institute of Preventive Medicine, in which both pregnancies were screened using a Quadruple test (maternal age with alphafetoprotein (AFP), unconjugated oestriol (uE<jats:sub>3<\/jats:sub>), total or free \u03b2\u2010human chorionic gonadotrophin (hCG) and either free \u03b1\u2010hCG or inhibin\u2010A as the fourth serum marker).<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Among women who had a false\u2010positive result in their initial pregnancy, the false\u2010positive rate in the subsequent pregnancy was high: 20% (46\/229), about three times higher than both the overall observed false\u2010positive rate (6.6%), and the expected false\u2010positive rate, in subsequent pregnancies that were false\u2013positive in their initial pregnancy (7.5%) (<jats:italic>p<\/jats:italic> &lt; 0.001). This arises because serum marker levels in one pregnancy are associated with the levels in a subsequent pregnancy. Using the slope (the regression coefficient <jats:italic>b<\/jats:italic>) of each marker level in a subsequent pregnancy regressed on the value in the first pregnancy, it is possible to adjust all marker values in a subsequent pregnancy to allow for the higher\u2010than\u2010expected false\u2010positive rate. This can be done by dividing the observed MoM value for each marker by the \u2018expected\u2019 MoM, which is the MoM value in a previous pregnancy raised to the power <jats:italic>b<\/jats:italic>.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>If a woman has had a false\u2010positive result in one pregnancy, she is much more likely to have a false\u2010positive screening result in a subsequent pregnancy than women in general. The problem can be avoided by adjusting the serum markers in all women who have been screened in a previous pregnancy and who have not had a previous pregnancy with Down syndrome. Copyright \u00a9 2004 John Wiley &amp; Sons, Ltd.<\/jats:p><\/jats:sec>","DOI":"10.1002\/pd.890","type":"journal-article","created":{"date-parts":[[2004,5,21]],"date-time":"2004-05-21T13:00:46Z","timestamp":1085144446000},"page":"389-392","source":"Crossref","is-referenced-by-count":17,"title":["Prenatal screening for Down syndrome: the problem of recurrent false\u2010positives"],"prefix":"10.1002","volume":"24","author":[{"given":"Nicholas J.","family":"Wald","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wayne J.","family":"Huttly","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alicja R.","family":"Rudnicka","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2004,5,21]]},"reference":[{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1096-8628(19960111)61:2<154::AID-AJMG10>3.0.CO;2-T"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/pd.1970140416"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0223(199807)18:7<706::AID-PD338>3.0.CO;2-W"},{"issue":"4","key":"e_1_2_1_5_1","first-page":"A285","article-title":"Trends in maternal serum markers in successive pregnancies suggest additional maternal factors influence levels","volume":"57","author":"Mooney RA","year":"1995","journal-title":"Am J Med Genet"},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.1136\/ewjm.173.3.180"},{"key":"e_1_2_1_7_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0223(199701)17:1<39::AID-PD35>3.0.CO;2-N"},{"key":"e_1_2_1_8_1","doi-asserted-by":"publisher","DOI":"10.1002\/pd.430"},{"key":"e_1_2_1_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(81)92269-8"},{"key":"e_1_2_1_10_1","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.297.6653.883"},{"key":"e_1_2_1_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0223(199703)17:3<285::AID-PD71>3.0.CO;2-A"},{"key":"e_1_2_1_12_1","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0223(199602)16:2<143::AID-PD825>3.0.CO;2-F"}],"container-title":["Prenatal Diagnosis"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fpd.890","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/pd.890","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,11,16]],"date-time":"2023-11-16T17:14:14Z","timestamp":1700154854000},"score":1,"resource":{"primary":{"URL":"https:\/\/obgyn.onlinelibrary.wiley.com\/doi\/10.1002\/pd.890"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,5]]},"references-count":11,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2004,5]]}},"alternative-id":["10.1002\/pd.890"],"URL":"https:\/\/doi.org\/10.1002\/pd.890","archive":["Portico"],"relation":{},"ISSN":["0197-3851","1097-0223"],"issn-type":[{"value":"0197-3851","type":"print"},{"value":"1097-0223","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,5]]}}}