Ductus venosus flow
Reversed a-wave
At 11-13 weeks reversed a-wave is found in about:
- Euploid fetuses 3%
- Fetuses with trisomy 21 65%
- Fetuses with trisomy 18 55%
- Fetuses with trisomy 13 55%
Reversed a-wave is more common if:
- The gestation is 11 than 13 weeks.
- The fetal nuchal translucency is high.
- The maternal serum PAPP-A is low.
- The mother is Black.
Reversed a-wave is associated with increased risk for:
- Chromosomal abnormalities
- Сardiac defects
- Fetal death
However, in about 80% of cases with reversed a-wave the pregnancy outcome is normal.
