Urinary estriol for assessment of fetoplacental function.

A total of 1,607 urinary estriol determinations were performed in 447 patients with normal and complicated pregnancies. In general, the test provided reliable information concerning fetal status, particularly in pregnancies complicated by toxemia, diabetes, and postmaturity. When measured consecutively, a drop of 50% or more in estriol level usually should be considered a significant index of fetal distress. Limitations of the test and several compensatory measures aimed at minimizing inaccuracy are discussed.