Threatened abortion studied by estradiol-17 beta in serum and ultrasound.

One hundred women were admitted to the hospital between 7 and 18 weeks' gestation because of vaginal bleeding and threatened abortion. Serum concentration of estradiol-17 beta was determined by radioimmunoassay. Ultrasound examination using a gray-scale scanner was performed as well. The values for prediction of abortion or successful outcome of pregnancy were calculated for estradiol (E2) and ultrasound separately and in combination. Prediction of abortion from a low E2 concentration combined with an ultrasound examination showing no fetal life was found to be totally reliable. Prediction of successful outcome of pregnancy from either a normal E2 or an ultrasound examination showing fetal life, or both, was 79.5% reliable. If no signs of fetal life were found by ultrasound examination from 10 weeks' gestation on, the pregnancy was doomed. Before this gestational age, measurements of E2 in serum gave supplementary information concerning the outcome of the threatened pregnancy.