Serum or plasma total unconjugated
estriol and total
estriol glucuronide fractions were measured in 14 patients with unaborted
hydatidiform mole between 11 and 25 weeks of gestation and in 20 normal pregnant patients between 8 and 17 weeks of gestation. The
estriol fractions were separated by
solvent partition, and the
estriol was measured by radioimmunoassay using antiserum against estriol-16-17-dihemisuccinate conjugated to
bovine serum albumin. The values (means and ranges) found in normal pregnant patients were as follows:
estriol 1.3 ng/ml (0.3-2.9);
estriol glucuronide, 11.1 ng/ml (4.7-24.8). Wide ranges of values were found in patients with
molar pregnancies compared to those with normal pregnancies of equivalent gestation, some values being within the upper range of normal and others being well below the normal range. Of the 14
molar pregnancies studied, 9 (64%) were associated with serum
estriol values which were below the ranges for normal pregnancy, and 8 (57%) were associated with similarly low
estriol glucuronide values. The incidences of low
estriol and
estriol glucuronide values were less than those reported for low urinary
estriol excretion in
hydatidiform moles. No correlation was found between any of the serum
estriol fractions and the serum hCG values or with the presence of theca
lutein cysts in the ovaries. It was suggested that the trophoblast was the principal source of
estriol in these
molar pregnancies.