Table 2.
Genetic Sonogram: Statistically Significant* Associations With Down Syndrome
| Finding | Down Syndrome | Unaffected Pregnancies | LR+ | LR− |
|---|---|---|---|---|
| Major malformation | 5/59 (8.5%) | 38/7,783 (0.49%) | 17 | 0.92 |
| Nuchal skinfold (6 mm or greater) | 6/33 (18%) | 24/6,473 (0.37%) | 49 | 0.82 |
| Femur length (less than 0.91 MoM) | 16/56 (29%) | 514/7,761 (6.6%) | 4.6 | 0.73 |
| Humerus length (less than 0.89 MoM) | 3/26 (12%) | 89/3,840 (2.3%) | 5.0 | 0.90 |
| Echogenic intracardiac focus (either ventricle) | 15/53 (28%) | 345/7,725 (4.5%) | 6.3 | 0.75 |
| Pyelectasis (3 mm or greater) | 4/55 (7.3%) | 103/7,777 (1.3%) | 5.5 | 0.94 |
| Marked echogenic bowel (bright as bone) | 2/55 (3.6%) | 12/7,778 (0.15%) | 24† | 0.96† |
| Moderate echogenic bowel | 6/55 (11%) | 28/7,777 (0.36%) | 30† | 0.89† |
| Ventriculomegaly (10 mm or greater) | 3/54 (5.6%) | 17/7,767 (0.22%) | 25 | 0.95 |
| No markers present‡ | 21/59 (36%) | 6,775/7,783 (87%) | — | 0.41 |
LR, likelihood ratio; MoM, multiples of the median.
*
P<.005, χ2 test.
†
For either marked or moderate echogenic bowel, LR+ is 28 and LR− is 0.86.
‡
Excluding humerus length.