Plasma unconjugated estriol values in high-risk pregnancy.

The usefulness of plasma estriol concentrations in the management of high-risk pregnancy is controversial. In this study, serial plasma unconjugated estriol (E3) concentrations determined by radioimmunoassay were evaluated in 321 patients with high-risk pregnancy for correlation with fetal and neonatal performance. A plasma E3 concentration of 4 ng. per milliliter or less in late pregnancy correlated significantly with low one-and five-minute Apgar scores and selected neonatal problems in pregnancies complicated by chronic hypertension and intrauterine growth retardation, with a similar trend for pregnancies complicated by moderate and severe pre-eclampsia. Most perinatal deaths in the study were associated with acute problems which began during labor and delivery, or fetal death occurred before early intervention was practical. Therefore, the perinatal mortality rate is not likely to be influenced by the use of E3 values, and the perinatal mortality rate is not a realistic measure of the usefulness of plasma E3 values in management of high-risk pregnancy. Low plasma E3 values were not always ominous, and for this reason it is suggested that clinical indications and the results of other tests for fetal-placental function be considered along with plasma E3 values in the selection of patients for early delivery to reduce the possibility of inappropriate intervention.