[Variation in total and unbound plasma cortisol levels throughout labor in normal and anencephalic pregnancies]

Total and unbound plasma Cortisol levels have been evaluated throughout labour in women delivering normal and anencephalitic infants. The sharp increase in total Cortisol usually observed in maternal plasma during labour does not occur in women bearing an anencephalitic foetus. This Cortisol binding capacity of Transcortin being the same, both in the normal and the pathological groups, it is shown that in anencephaly, unconjugated Cortisol levels are also lowered. The maternal contribution to the plasma Cortisol increase being identical in all cases, our data suggest that in anencephaly, a lack of foetal contribution might be responsible for the low Cortisol levels observed throughout labour.