Bedside estimation of Down syndrome risk from second-trimester ultrasound prenasal thickness
Article first published online: 1 DEC 2009
Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound in Obstetrics & Gynecology
Volume 34, Issue 6, pages 629–633, December 2009
How to Cite
Maymon, R., Moskovitch, M., Levinsohn-Tavor, O., Weinraub, Z., Herman, A. and Cuckle, H. (2009), Bedside estimation of Down syndrome risk from second-trimester ultrasound prenasal thickness. Ultrasound Obstet Gynecol, 34: 629–633. doi: 10.1002/uog.7480
- Issue published online: 1 DEC 2009
- Article first published online: 1 DEC 2009
- Manuscript Accepted: 8 JUN 2009
- Down syndrome;
- estimated risk;
- prenasal thickness;
To construct tables for ‘bedside’ estimation of Down syndrome risk based on maternal age and ultrasound prenasal thickness (PT) measurements.
Likelihood ratios were calculated using a log Gaussian model of the PT distribution in multiples of the gestational age-specific median (MoM). The model parameters were derived from 80 Down syndrome and 850 unaffected pregnancies scanned at 14–27 weeks; these data had been published previously, in three series, except for 18 Down syndrome and 119 affected pregnancies. The means were estimated as the median, and the SDs as the 10th–90th range divided by 2.563.
A log Gaussian model fitted well the distribution of PT values in Down syndrome and unaffected pregnancies with medians of 1.31 MoM and 1.01 MoM, and log10 SDs of 0.075 and 0.082, respectively.
The tables provide a simple ‘bedside’ estimation of Down syndrome risk without the need for computerized software or complicated calculations. More prospective data on PT in combination with other first- and second-trimester screening markers are needed. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.