Table 29. Average blood flow rates to various fetal tissues.

Tissue	Relevant Symbol	% CO
Placenta	$Q_{\text{plac}}^{\text{f}}$	23.9
Gut	$Q_{\text{gutx}}^{\text{f}}$	6.8
Kidneys	$Q_{\text{kidn}}^{\text{f}}$	5.4
Adrenals	—	4.8
Lower Body	—	27.1
Heart	—	3.0
Brain	$Q_{\text{bran}}^{\text{f}}$	14.3
Upper Body	—	13.6
Total		98.9

The values shown indicate mean percentages of total cardiac output (% CO), and are based upon data of Rudolph et al. [65]. In some cases, these authors made multiple measurements for a single fetus; for the purposes of computing the means in this table we only used the first measurement for each fetus. For many of the individual fetuses measured by Rudolph et al. [65], the percentages summed to 99 or 101; this can be explained by the fact that percentage values were rounded to the nearest unit. In some cases, however, the percentages for an individual fetus summed to a total less than 99 (and, in one case, as low as 88). The reason for these larger discrepancies is unclear, but they were rare and we decided to use the values from all 33 fetuses to compute the averages reported here.