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Nuchal Translucency Screening ~ Risk Table

Estimated risk for trisomie 21 (Down's) in relation to maternal age.
Maternal Age (years) At 12 Weeks At Birth
20 1 in 1068 1 in 1527
30 1 in 626 1 in 895
32 1 in 461 1 in 659
35 1 in 249 1 in 356
38 1 in 117 1 in 167
40 1 in 68 1 in 97
41 1 in 51 1 in 73
42 1 in 38 1 in 55

Effect of maternal age and gestation on risk:

As can be seen from the chart, women of all ages are at risk of having a baby with Down’s syndrome but this risk increases as the woman gets older.

The earlier the gestation, the higher the risk. The risk reduces for all women as the pregnancy progresses because many affected babies will miscarry spontaneously.