Table 1.
Maternal and gestational age, and NT in Down's syndrome and unaffected pregnancies
| Down's syndrome | Unaffected | |
|---|---|---|
| Median age (years) | 39 | 34 |
| Median CRL (mm) | 63 | 62 |
| Gestational age | ||
| 10 weeks gestation | 2 | 243 |
| 11 weeks gestation | 20 | 4270 |
| 12 weeks gestation | 50 | 10,363 |
| 13 weeks gestation | 34 | 7764 |
| Total | 106 | 22,640 |
| Median NT (mm) | 2.7 | 1.5 |
| Median NT (MoM) | ||
| 10 weeks gestation | 3.93 | 1.02 |
| 11 weeks gestation | 2.22 | 0.98 |
| 12 weeks gestation | 1.86 | 1.02 |
| 13 weeks gestation | 1.55 | 0.99 |
CRL, crown rump length; NT, nuchal translucency, MoM, multiple of the median