[The monitoring of pregnancy in rhesus-sensitized women by a quantitative determination of bilirubin in amniotic fluid (author's transl)].

The prognostic accuracy of spectro photometric examination of the amniotic fluid and of a specific method for the determination of free bilirubin in the amniotic fluid are compared. Amniocentesis was carried out 166 times in 85 sensitized rhesus-negative pregnant women. Spectro photometric examination gave a misleading assessment in 28% of the cases. This applied particularly to Liley's Zone II, in which the presence or absence of haemolytic disease of the newborn was incorrectly predicted in up to 70% of the cases. By contrast, on evaluation of the cases using specific determination of free bilirubin, not a single value obtained after the 34th week of pregnancy led to false assessment of the fetal condition. There is a stong correlation between the extent of fetal damage and the bilirubin content of the amniotic fluid.