15alpha-Hydroxyoestriol and other polar oestrogens in pregnancy monitoring

Abstract

Although oestriol measurements are well established for the assessment of 'at risk' pregnancies, there are a number of other oestrogens, excreted during pregnancy, which contain additional hydroxyl groups and might be more sensitive indicators of the condition of mother or fetus. Some of these result from the action of hydroxylases possibly present only in the fetus and others from maternal hydroxylations. We review the evidence for the biosynthesis of these polar oestrogens, summarise methods of measurement, and compare values obtained in normal and pathological pregnancies. There is as yet insufficient evidence to enable their potential value to be confirmed.

PIP: Attempts to assess "at-risk" pregnancies may be aided by measuring a number of polar estrogens excreted during pregnancy which contain additional hydroxy groups. 2 hydroxy groups show promise as sensitive indicators of maternal or fetal condition: 15-hydroxylations which appear to be predominantly fetal reactions, and 18-hydroxylations which can take place in both the fetus and adult. Excretion rates of the 15- and 18-hydroxy compounds were compared with known estriol excretion rates; in normal pregnancies the levels of estriol and 15 alpha-hydroxyestriol (15 alpha) in maternal blood and urine closely paralleled. In the pathological pregnancies, little indication that 15 alpha measurements are valuable in prediction of fetal morbidity or death was discovered; though in preeclamptic toxemia patients, 15 alpha levels became subnormal 1 day-several weeks before death, and urinary levels of 15 alpha were often low when birth weights were low. During measurement of several estriols throughout pregnancy, a good correlation between 18-hydroxyestriol and 15 alpha was shown; however, measurements from 20 at-risk pregnancies did not show such a correlation.