Plasma estrogens in the assessment of fetoplacental function.

A retrospective study has been undertaken to assess the diagnostic value of plasma estriol (E3) determinations, as compared with determinations of other biochemical parameters, in predicting the outcome of pregnancy. The normal levels of plasma unconjugated and total E3 were determined on weekly samples obtained during the third trimester of 258 normal pregnancies. Weekly concurrent specimens of plasma and 24-hour urine collections were obtained from 17 high-risk pregnancies associated with hypertension, intrauterine growth retardation and diabetes. Determination of plasma unconjugated and total E3 were made along with human placental lactogen (HPL), urinary E3, and other biophysical parameters such as the oxytocin challenge test, non-stressed test, ultrasonography, etc. The results of plasma E3 were not reported nor used for the clinical management of the patient. The data suggests that weekly plasma determinations were of little value in the assessment of feto-placental status. Some observations on the extent of variability of plasma E3 are discussed.