Serial betamethasone administration: Effect on maternal salivary estriol levels

OBJECTIVE: Maternal salivary estriol levels are an indirect measure of feta l adrenal activity, which may be affected by administration of betamethason e. The objective was to compare sequential salivary estriol levels in patie nts receiving serial betamethasone therapy with those of healthy pregnant p atients. STUDY DESIGN: Ten patients at high risk for preterm delivery were asked to obtain salivary specimens before and 1 to 2 days after each administration of weekly betamethasone treatments between 24 and 32 weeks' gestation. Thes e values were compared with those of specimens obtained throughout gestatio n in healthy women who were not delivered preterm. Unconjugated salivary es triol was measured with a sensitive and specific enzyme-linked immunoassay (Biex, Inc, Dublin, Calif). RESULTS: The effect of betamethasone on salivary estriol levels did not cha nge with time, showing an average of 23.1% drop from pretreatment to posttr eatment levels but rebounding to the same starting level before the next do se. When weekly pretreatment values were looked at across time, the geometr ic mean of the individual patients' slopes did not differ significantly fro m no change. The same was true of the posttreatment values. The rate of cha nge with advancing gestation was compared between 182 control subjects and the 10 study subjects. The average change was +8.8% per week in the control subjects and -1.3% per week in the study patients (P=.003). CONCLUSIONS: Maternal administration of betamethasone significantly suppres sed salivary estriol levels. These levels returned to pretreatment Values e ach week before the next dose; however, the rise normally associated with a dvancing gestational age was not observed.