Fetus Oxygen consumption

In addition, the metabolic effects of insulin ultimately increase fetal oxygen consumption. The circulation of the fetus is unique specifically, because blood in the fetal descending aorta contains a portion of venous return after tissue perfusion, the increased rate of consumption of oxygen by fetal tissues decreases the arterial oxygen concentration of the fetus. The fetal tissues supplied by this circulation (which include most of the mass of the fetus) are then at risk for inadequate tissue oxygenation. 

The fetus requires oxygen on a moment-to-moment basis. Assuming a fetal oxygen consumption of 6 ml/min/kg of fetal weight, a term fetus (weighing 3 kg) requires about 18 ml of 02 per minute. In view of this... 

Figure 8 Effects of 20-mill adenosine infusion (3 (imol/kg) into an unanesthetized, nomioxic midgestation sheep fetus in utero on cerebral oxygen delivery and consumption. While oxygen delivery did not show any significant change, cerebral oxygen consumption fell. p < 0.05, paired t-test versus preinfusion level. (From Ref 161.)...

Since the consumption of oxygen by the fetus is not considered in this study, a maternal blood velocity change to a zero velocity would result in a fetal end capillary oxygen concentration that is equal to the... 

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