Salivary oestriol in normal pregnancy

A comparison of saliva, plasma unconjugated and plasma total oestriol levels throughout normal pregnancy

Saliva unconjugated, plasma unconjugated and plasma total oestriol (E3) levels were measured longitudinally, by radioimmunoassay, in 25 normal women from 13 weeks gestation until delivery. The increase in salivary unconjugated oestriol closely paralleled that of plasma unconjugated oestriol and to a lesser extent that of plasma total oestriol. In each patient the percentage value of salivary E3/plasma unconjugated E3 x 100 was virtually constant throughout pregnancy but this percentage varied from one patient to another (mean 14.4%). The overall correlation coefficient (r) for salivary and plasma unconjugated E3 was 0.90. The variability in salivary levels in samples collected at daily, hourly, 15 min and 5 min intervals (12.7, 13.4, 10.1 and 9.3%) was similar to that previously described for plasma unconjugated E3. There was no distinct pattern in diurnal variation. It seems probable that measurement of salivary E3 could adequately replace that of plasma unconjugated E3 in the assessment of fetoplacental function.

Salivary oestriol in normal and abnormal pregnancies

Profiles of daily salivary oestriol concentrations throughout the third trimester of pregnancy have been constructed for 14 normal and 11 abnormal pregnancies. Day-to-day variations were significantly higher than those reported for unconjugated oestriol in plasma or serum. A sustained decline in salivary oestriol concentrations was observed in one pregnancy in which intrauterine death occurred. Sustained falls were also observed in two pregnancies in which a healthy infant was born at term. In all other patients a normal salivary oestriol profile correlated with a favourable outcome. Salivary oestriol measurements provide similar information to plasma unconjugated oestriol measurements while offering the advantages of a simple, non-invasive sample collection procedure.

Influence of sampling time on salivary oestriol concentrations in pregnant women

Saliva specimens were collected at weekly intervals during the third trimester of 61 uncomplicated pregnancies. Oestriol concentrations, measured in samples collected in the early morning from fasting, recumbent subjects, were used to construct a provisional normal range. This proved to be higher than the corresponding normal range reported from another laboratory applying the same method to samples obtained at random from a different population of ambulant subjects. Interlaboratory variation in the assay of salivary oestriol was not sufficient to account for the difference in normal range. It is concluded that consideration should be given to the timing of sample collection if salivary oestriol concentration is to be monitored as a possible means of assessing fetoplacental function. A normal range for salivary oestriol concentration versus gestational age obtained from women sampled randomly may not be appropriate for monitoring patients with 'at-risk' pregnancies who are normally bed-rested.