1 Department of clinical biochemistry, Faculty of Health Sciences, Aarhus University, Aarhus University2 Department of Clinical Medicine - Department of clinical biochemistry, Department of Clinical Medicine, Health, Aarhus University3 Department of Clinical Medicine - Department of clinical biochemistry, Department of Clinical Medicine, Health, Aarhus University
Objectives At Aarhus University Hospital, Denmark, the first trimester screening has been performed with the blood sample taken as early as gestational week 7 since 2003. We hereby present the status for the screening program. Methods: The study includes singleton pregnancies with complete first trimester screening and the blood sample taken between 7 weeks + 5 days to 13 weeks + 6 days from November 2003 to March 2011. Results: 159 out of 173 cases of trisomy 21 were diagnosed in the first trimester screening (detection rate 92%). When the blood sample was taken before the 10th gestational week, the detection rate of trisomy 21 was 96% (99 out of 103), whereas 86% were detected (50 out of 60) after 10th week (Chi square = 0.03). For trisomy 18 and trisomy 13, 26 out of 32 (81%) were detected before 10th gestational week, and 9 out of 13 (69%) after the 10th gestational week (N.S). Conclusions: Screening for fetal aneuploidy can be performed with good results with the blood sample taken as early as the 7th week of gestation. Taking the blood sample before the 10th gestational week showed a high detection rate of fetal trisomy 21, with no difference in the detection of fetal trisomy 18, 13 or triploidy.