Abnormal ductus venosus blood flow in trisomy 21 fetuses during early pregnancy

OBJECTIVE: Our purpose was to assess the ductus venosus blood flow in triso my 21 fetuses in the first half of pregnancy and the relation of this blood flow to nuchal thickness. STUDY DESIGN: The ductus venosus blood flow has been studied in 534 consecu tive fetuses between 10 and 18 weeks of gestation who were undergoing prena tal invasive diagnostic procedures. Before the sampling, the velocity durin g atrial contraction, the pulsatility index for veins, and the ratio of sys tole-end-systole to diastole were established in the Doppler waveforms and eventually correlated with the fetal karyotype. RESULTS: Ductus venosus waveforms were successfully obtained in 82% of the pregnancies. Eleven fetuses were found to have trisomy 21;the pulsatility i ndex was abnormally increased (>95th percentile) in 73% (8/11), the ratio o f systole-end-systole to diastole was abnormally increased in 45% (5/11), a nd the velocity during atrial contraction was decreased (<5th percentile) i n 27% (3/11). CONCLUSIONS: An abnormally increased ductus venosus pulsatility index was f ound in a substantial proportion of early trisomy 21 fetuses, and this was apparently independent of nuchal thickening.