Ultrasound and estradiol plasma levels in threatened abortion

Ultrasound examination and unconjugated estriol assay were performed in 111 women with threatened abortion between the 6th and the 20th week of pregnancy. In viable pregnancies, fetal echoes and fetal heart movements were always observed by sonar from the 10th week onward and estradiol levels always increased above 30 pg/ml from the 13th week. Both ultrasound and estriol assay showed high percentages of uncertain prognostic indication on pregnancy outcome when examinations were performed during the first weeks of pregnancy. However, in the same period estriol levels higher than 30 pg/ml were always correlated with the favourable outcome of pregnancy, since no abortion occurred in subjects with detectable estriol values. During the second trimester ultrasound and estradiol results were normal in all viable pregnancies, while they were abnormal in 71.4% of pregnancies which failed to continue. Estriol values were always undetectable when fetuses could not be identified by sonar or they were dead. These data seem to demonstrate that both methods have similar prognostic value in patients with threatened abortion. However both sonar examination and estriol levels sometimes failed in predicting subsequent pregnancy interruptions, suggesting that abortions were not related to either fetal or placental alterations.