OBJECTIVES: In Denmark a new national guideline for prenatal screening and diagnosis was issued in 2004 according to which all pregnant women should be offered a first-trimester combined risk assessment for trisomy 21 (T21). The aim of this study was to investigate whether the new screening strategy for T21 has changed the gestational age at which trisomy 18 (T18) and trisomy 13 (T13) are diagnosed prenatally, and the number of infants born with T18 or T13. METHODS: We collected from the Danish Cytogenetic Central Register information on all prenatal and postnatal chromosome analyses for T18 or T13, registered from 1997 to 2007. Information on first-trimester screening results was collected from each department of obstetrics and gynecology performing the nuchal translucency scans. The cut-off used for referral to invasive diagnostic testing for T21 and for T18/T13 was 1 : 300 and 1 : 150 at screening, respectively. RESULTS: In total, there were 435 cases with T18 and 168 cases with T13 between 1997 and 2007 in Denmark. The estimated incidence of T18 and T13 at the time of delivery was calculated as 2.5 and 1.6 per 10 000 deliveries, respectively. The number (proportion) of cases diagnosed before week 18 increased significantly, from 63 (59.4%) in 1997 and 1998 to 90 (80.4%) in 2006 and 2007 (P < 0.001). In addition, the number of T18 and T13 cases diagnosed prenatally after week 22 or postnatally decreased significantly, from 34 (32.1%) in 1997 and 1998 to seven (6.3%) in 2006 and 2007 (P < 0.0001). For women participating in first-trimester risk assessment in 2006 and 2007, the detection rate of T18 and T13 was 78.8% (95% CI, 71.0-86.7%). CONCLUSION: The number of T18 and T13 fetuses diagnosed before week 18 increased significantly after the introduction of a combined first-trimester screening strategy for T21 in Denmark. In addition, the total number of fetuses diagnosed late in pregnancy and infants born with T18 or T13 decreased significantly. The national detection rate for T18 and T13 in the first trimester is comparable with detection rates found in modeled datasets and other prospective studies.
OBJECTIVES: In Denmark a new national guideline for prenatal screening and diagnosis was issued in 2004 according to which all pregnant women should be offered a first-trimester combined risk assessment for trisomy 21 (T21). The aim of this study was to investigate whether the new screening strategy for T21 has changed the gestational age at which trisomy 18 (T18) and trisomy 13 (T13) are diagnosed prenatally, and the number of infants born with T18 or T13. METHODS: We collected from the Danish Cytogenetic Central Register information on all prenatal and postnatal chromosome analyses for T18 or T13, registered from 1997 to 2007. Information on first-trimester screening results was collected from each department of obstetrics and gynecology performing the nuchal translucency scans. The cut-off used for referral to invasive diagnostic testing for T21 and for T18/T13 was 1 : 300 and 1 : 150 at screening, respectively. RESULTS: In total, there were 435 cases with T18 and 168 cases with T13 between 1997 and 2007 in Denmark. The estimated incidence of T18 and T13 at the time of delivery was calculated as 2.5 and 1.6 per 10 000 deliveries, respectively. The number (proportion) of cases diagnosed before week 18 increased significantly, from 63 (59.4%) in 1997 and 1998 to 90 (80.4%) in 2006 and 2007 (P < 0.001). In addition, the number of T18 and T13 cases diagnosed prenatally after week 22 or postnatally decreased significantly, from 34 (32.1%) in 1997 and 1998 to seven (6.3%) in 2006 and 2007 (P < 0.0001). For women participating in first-trimester risk assessment in 2006 and 2007, the detection rate of T18 and T13 was 78.8% (95% CI, 71.0-86.7%). CONCLUSION: The number of T18 and T13 fetuses diagnosed before week 18 increased significantly after the introduction of a combined first-trimester screening strategy for T21 in Denmark. In addition, the total number of fetuses diagnosed late in pregnancy and infants born with T18 or T13 decreased significantly. The national detection rate for T18 and T13 in the first trimester is comparable with detection rates found in modeled datasets and other prospective studies.
Authors: Rachèl V van Schendel; Johanna H Kleinveld; Wybo J Dondorp; Eva Pajkrt; Danielle R M Timmermans; Kim C A Holtkamp; Margreet Karsten; Anne L Vlietstra; Augusta M A Lachmeijer; Lidewij Henneman Journal: Eur J Hum Genet Date: 2014-03-19 Impact factor: 4.246
Authors: Neeltje M T H Crombag; Ynke E Vellinga; Sandra A Kluijfhout; Louise D Bryant; Pat A Ward; Rita Iedema-Kuiper; Peter C J I Schielen; Jozien M Bensing; Gerard H A Visser; Ann Tabor; Janet Hirst Journal: BMC Health Serv Res Date: 2014-09-25 Impact factor: 2.655
Authors: Katelijne Bouman; Marian K Bakker; Erwin Birnie; Lies Ter Beek; Caterina M Bilardo; Irene M van Langen; Hermien E K de Walle Journal: BMC Pregnancy Childbirth Date: 2017-01-05 Impact factor: 3.007
Authors: Rachèl V van Schendel; Carla G van El; Eva Pajkrt; Lidewij Henneman; Martina C Cornel Journal: BMC Health Serv Res Date: 2017-09-19 Impact factor: 2.655
Authors: Janneke T Gitsels-van der Wal; Pieternel S Verhoeven; Judith Manniën; Linda Martin; Hans S Reinders; Evelien Spelten; Eileen K Hutton Journal: BMC Pregnancy Childbirth Date: 2014-08-09 Impact factor: 3.007
Authors: Neeltje M T H Crombag; Hennie Boeije; Rita Iedema-Kuiper; Peter C J I Schielen; Gerard H A Visser; Jozien M Bensing Journal: BMC Pregnancy Childbirth Date: 2016-05-26 Impact factor: 3.007
Authors: Rachèl V van Schendel; Adriana Kater-Kuipers; Elsbeth H van Vliet-Lachotzki; Wybo J Dondorp; Martina C Cornel; Lidewij Henneman Journal: J Genet Couns Date: 2016-09-13 Impact factor: 2.537