[Alpha fetoprotein and neonatal jaundice. Contribution to the study of a physiopathologic mechanism].

The increase in the maternal plasma A.F.P. level is due to an hypoxia of the foetus. The prospective study of 851 single pregnancies shows that there is a significant rise in the A.F.P. levels during the last days of the pregnancy if the babies are going to exhibit a so-called physiological jaundice at birth: the decrease of the A.F.P. levels in these cases is four times slower than in normal cases. The prospective study of another group of 404 pregnancies gave the same results for the A.F.P. level of the blood of the umbilical cord. Statistical analysis showed that the pathological conditions capable of increasing the A.F.P. levels are related to neo-natal jaundice. The neo-natal jaundice may be due to a factor of foetal hypoxia capable of inducing an over stimulation of the foetal erythropoiesis. The results of this mechanism would be a quantitative disequilibrium between an increased hemolysis and a reduced bilirubine fixation capacity during the neo-natal period.