Umbillical venous volume inflow and liver size in normal and abnormal fetal development

In this thesis the following research objectives were addressed: To calculate umbilical venous volume flow from cross-sectional area and flow velocity measurements with emphasis on: (i) the reproducibility of component measurements; (ii) normal and abnormal fetal development, the latter also relative to umbilical artery velocimetry. To establish: (i) reproducibility and normal values for fetal liver volume as obtained by 3- dimensional ultrasound; (ii) its significance in identifying fetal growth restriction relative to head and upper abdominal circumference; (iii) its significance in identifying accelerated growth in fetuses of insulin dependent diabetic mothers. To determine: (i) normal values for fetal brain/liver volume ratio relative to gestational age; (ii) the relation between fetal brain/liver volume ratio and umbilical venous volume flow during normal and abnormal fetal development with emphasis on fetal growth restriction. To establish: (i) fetal behavioural state dependency of umbilical venous volume flow in late third trimester normal pregnancy; (ii) the impact of maternal plasma expansion and antihypertensive treatment on umbilical venous volume flow in pre-eclampsia