Correlation between umbilical vein blood flow and umbilical blood viscosity in normal and complicated pregnancies

Abstract

Umbilical vein blood flow (UVBF) was studied during the last 24 h before delivery using a combination of real-time and Doppler ultrasonic equipment in 64 normal and pathological pregnancies and the results were correlated with the values of whole blood viscosity taken from the umbilical vein after delivery. UVBF was reduced in the subgroup with chronic fetal distress (n = 14) (P less than 0.001) and the hypertensive pregnancies (n = 17) (P less than 0.05), whereas umbilical blood viscosity was increased only in the subgroup with chronic fetal distress (P less than 0.01) as compared with the normal pregnancies (n = 24). A significant positive correlation was observed between the umbilical blood viscosity and haematocrit values in all the groups of patients. UVBF and blood viscosity had a significant negative correlation in chronic fetal distress (P less than 0.001) and in hypertensive pregnancies (P less than 0.05), but not in normal or diabetic pregnancies (n = 9). Thus haemoconcentration leading to increased fetal blood viscosity may act as an aetiological factor in the reduction of UVBF in developing fetal distress.

Longitudinal umbilical vein blood flow changes in normal and growth‐retarded fetuses

“…Although blood flow velocity measurements are difficult to correctly obtain, it seems that in IUGR fetuses the umbilical blood flow velocity increase normally present in healthy fetuses with advancing gestation does not occur (10). The result of the present study agrees with those of Ferrazzi et al (11) and of Jouppila et al (24), who found that IUGR fetuses had a lower mean umbilical vein blood flow velocity than AGA fetuses.…”

“…A possible explanation for the reduced umbilical vein blood velocity in IUGR fetuses is the different blood viscosity between these fetuses and AGA fetuses. Jouppila et al (24) reported that an inverse correlation exists between umbilical vein blood viscosity and both umbilical blood flow volume and velocity. Furthermore, these authors found that umbilical cord blood viscosity is significantly increased in IUGR fetuses without maternal or fetal diseases compared with AGA fetuses.…”

Multiscale modeling of the cardiovascular system: application to the study of pulmonary and coronary perfusions in the univentricular circulation

“…The chosen viscosity value is close to the foetal one, which is higher than that in the adult circulation due to higher haematocrit (Jouppila et al, 1986;El Bouhmadi et al, 2000). HLHS patients are operated in the first days after delivery as this pathology is not compatible with life.…”

An assessment of ductus venosus tapering and wave transmission from the fetal heart

“…The first harmonic of this calculated pressure, corresponding to the fundamental frequency, was imposed as the BC at the DV inlet. The blood was assumed to have a density ρ = 1.05 × 10 3 kg/m 3 (Fernandez et al 1976) and a dynamic viscosity of µ = 4.2 × 10 −3 kg/ms (Jouppila et al 1986). Further details on the numerical implementation may be found in the Appendix A.…”