Ultrasonic assessment of cardiovascular geometry and function in the human fetus

A new technique of studying fetal cardiac geometry and function from two-dimensional real-time images is presented. A significant increase in left ventricular size with advancing gestational age was observed. Left ventricular cardiac output size with advancing gestational age was observed. Left ventricular cardiac output (LVCO) was 210 +/- 48 ml/min (Mean +/- 1 SD) between 27 and 33 weeks and 336 +/- 35 ml/min between 34 and 41 weeks gestation. Blood flow (mean flow) in the descending aorta during these two periods was 365 +/- 80 and 490 +/- 65 ml/min. In four fetuses, the LVCO per kg birth weight ranged between 114 and 123 ml/kg/min and the blood flow in the descending aorta between 168 ad 179 ml/kg/min. If total cardiac output is considered to be twice the LVCO, the proportion of total cardiac output being distributed through the descending aorta and placenta is about 75% and 45% respectively.