Doppler waveforms: the relation between ductus venosus and inferior vena cava.

This study was to assess whether or not there was correlation between the Doppler velocity waveform of the ductus venosus (DV) and inferior vena cava (IVC). A total of 142 healthy pregnant women were enrolled and divided into three groups according to the gestational weeks at the examination time. Group 1 was < or = 22 weeks; group 2 was between 22 and 28 weeks; and group 3 was > or = 28 weeks. Acuson 128xp was used to measure the Doppler velocity waveforms of DV and IVC by one experienced examiner. Doppler indices were used for analysis. Our results showed that, with the advance of pregnancy age, the resistance index of DV (DV-RI) and the preload index of IVC (IVC-PLI) were correlated with the gestational weeks, r = -0.247 and r = -0.540, respectively. There was a weak correlation between DV-RI and IVC-PLI, r = 0.202, p < 0.05; however, there was no significant correlation between DV-RI and IVC-PLI in group 1, group 2 or group 3. In conclusion, we report the first study on the correlation between DV-RI and IVC-PLI, which indicated the different roles of DV and IVC in fetal hemodynamics.