Comparison between serum estriol and urinary estrogens as indices of fetoplacental function

In order to compare the predictive efficacies of serum estriol and urinary estrogen excretion in early diagnosis of fetal distress, 255 patients with normal (N = 128) or complicated (N = 127) pregnancies were monitored with simultaneous determinations of serum estriol (radioimmunoassay) and urinary estrogen excretion/24 h (colorimetric method) after the 32nd week of pregnancy. There was no difference in the efficacies of these tests. Out of all 43 fetal distress cases, 40% were predicted by serum estriol and 33% urinary estrogens. In pre-eclampsia, the respective findings were 56% and 50%. Fetal distress was the most probable (88%) when both of the tests were low at the same time. In pregnancies complicated with diabetes or rhesus immunization both tests revealed normal findings apart from the presence of fetoplacental dysfunction. The choice between these tests must be based on other factors than the diagnostic accuracy.