First-trimester screening for trisomy 21 combining biochemistry and ultrasound at individually optimal gestational ages. An interventional study
Article first published online: 3 AUG 2004
Copyright © 2004 John Wiley & Sons, Ltd.
Volume 24, Issue 7, pages 541–545, July 2004
How to Cite
Borrell, A., Casals, E., Fortuny, A., Farre, M. T., Gonce, A., Sanchez, A., Soler, A., Cararach, V. and Vanrell, J. A. (2004), First-trimester screening for trisomy 21 combining biochemistry and ultrasound at individually optimal gestational ages. An interventional study. Prenat. Diagn., 24: 541–545. doi: 10.1002/pd.949
- Issue published online: 3 AUG 2004
- Article first published online: 3 AUG 2004
- Manuscript Accepted: 25 MAY 2004
- Manuscript Revised: 19 MAY 2004
- Manuscript Received: 19 NOV 2003
- nuchal translucency;
- Down syndrome;
- biochemical markers;
- first-trimester screening;
- Combined Test
To assess the effectiveness of the Combined Test in the prenatal detection of trisomy 21 in the general pregnant population using a new timing for the screening approach.
First-trimester maternal serum biochemical markers (pregnancy-associated plasma protein-A and free-β hCG) were determined in maternal serum at 7 to 12 weeks. Fetal nuchal translucency and gestational age were assessed at the 10- to 14-week ultrasound scan. A combined risk was estimated and delivered to the women the same day. When the risk was 1:250 or above, chorionic villus sampling was offered.
Mean gestational age at biochemistry was 9.4 weeks, being 12.3 at ultrasound. In the 2780 studied pregnancies with a complete follow-up, observed detection rates were 88% (7/8) for trisomy 21 and 75% (3/4) for trisomy 18, with a 3.3% (92/2765) false-positive rate.
The Combined Test, assessing biochemistry and ultrasound at individually optimal ages in the first trimester, showed an 88% detection rate for trisomy 21 with a remarkably reduced false-positive rate (3.3%). Copyright © 2004 John Wiley & Sons, Ltd.