Is the fetus "scalped" in labour?

Capillary blood-flow and tissue oxygenation of the scalp and/or forearm skin were measured in the three adult volunteers. Skin pressure required to occlude circulation was much lower for the scalp than for the forearm skin, and tissue oxygenation fell rapidly when capillary blood-flow fell below about 3 ml/100 g tissue/min. Since scalp circulation is not representative of the general circulation when pressure is applied, the tissue oxygenation level of the fetal scalp in labour (obtained by direct sampling or by transcutaneous electrodes) is not a good indicator of the well-being of a fetus.