Comparison of ductus venosus blood flow waveform indices of 607 singletons with 133 multiples at 10-14 weeks gestation

Abstract Abnormal flow profiles in the ductus venosus during early pregnancy may aid in diagnosing chromosomopathies, malformations, congenital heart disease, and twin-twin transfusion syndrome in monochorionic twins. Whereas reference values of ductus venosus flow velocities and waveform indices for the late first and early second trimester have been reported in singletons, similar reference values for multiple pregnancies have not been established in this age group. Therefore, the aim of the present ultrasound study in 119 multichorionic and 14 monochorionic multiples in human fetuses between 10–14 weeks of gestation was to establish reference values for ductus venosus flow waveform indices for multiple pregnancies. Data in multiples were compared with those of 607 singletons. Analysis of the ductus venosus (DV) flow velocity waveforms consisted of the calculation of the pulsatility index (PIV) and peak velocity index (PVIV) for veins. Comparing the data of singletons and multichorionic multiples, no statistically significant differences were observed between the two groups in any of the assessed Doppler parameters. The DV Doppler parameters of the 14 monochorionic twins that were analysed separately in order to avoid any potential bias from preclinical twin-twin transfusion syndrome were also found within the normal ranges. In the study population fetal heart rate did neither significantly correlate with PIV nor with PVIV. PIV and PVIV decreased from 10 to 14 weeks gestation. A 2.9% rate of absent or reverse flow during atrial contraction in normal fetuses at 10–14 weeks gestation was found and needs to be taken into consideration when this pattern is defined abnormal in screening tests for fetal chromosomopathies or congenital heart disease.