Serial betamethasone administration: effect on maternal salivary estriol levels.

OBJECTIVE: Maternal salivary estriol levels are an indirect measure of fetal adrenal activity, which may be affected by administration of betamethasone. The objective was to compare sequential salivary estriol levels in patients receiving serial betamethasone therapy with those of healthy pregnant patients. 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. These values were compared with those of specimens obtained throughout gestation in healthy women who were not delivered preterm. Unconjugated salivary estriol 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 change with time, showing an average of 23.1% drop from pretreatment to posttreatment levels but rebounding to the same starting level before the next dose. When weekly pretreatment values were looked at across time, the geometric mean of the individual patients' slopes did not differ significantly from no change. The same was true of the posttreatment values. The rate of change 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 suppressed salivary estriol levels. These levels returned to pretreatment values each week before the next dose; however, the rise normally associated with advancing gestational age was not observed.

Comparison between oral and intramuscular dexamethasone in suppressing unconjugated estriol levels during the third trimester.

OBJECTIVES: Unconjugated estriol production depends on fetal adrenal androgen precursors. Fetal exposure to exogenous glucocorticoids results in adrenal suppression with a subsequent decrease in maternal serum unconjugated estriol levels. We compared the efficacy between oral and intramuscular dexamethasone in maternal serum unconjugated estriol suppression at 48 hours after the initial dose among women at risk for preterm delivery. STUDY DESIGN: Twenty-four gravidas at risk for preterm delivery were randomized to receive either 6 mg intramuscular or 8 mg oral dexamethasone every 12 hours for a total of 4 doses. Blood samples (9 mL) were obtained before the initial dexamethasone administration and again after the fourth dose. Serum was separated and frozen at -70 degreesC and subsequently underwent batch analysis. Unconjugated estriol levels were determined by radioimmunoassay with intra-assay and interassay coefficients of variation of 7.9% and 5.5%, respectively. All values are reported as mean +/- SD. The primary statistical analysis was a t test, with P <.05 considered significant. RESULTS: At the time of dexamethasone administration, gestational ages in both groups were similar. Predexamethasone and postdexamethasone unconjugated estriol levels were also similar between the intramuscular and oral groups (5.39 +/- 3.99 vs 1.80 +/- 2.49 ng/mL and 6.05 +/- 3.00 vs 1.61 +/- 1.03 ng/mL, respectively, P >.05). No difference in percent decrease in unconjugated estriol levels was found between the intramuscular (0.67 +/- 0.24) and oral (0.65 +/- 0.39) groups. CONCLUSION: Oral dexamethasone (8 mg) produces similar maternal serum unconjugated estriol suppression compared with intramuscular dexamethasone (6 mg) when evaluated 48 hours after administration.

Flavonoids in grapefruit juice inhibit the in vitro hepatic metabolism of 17 beta-estradiol.

Naringenin, quercetin and kaempferol, which may be found in glycoside form in natural compounds such as grapefruit, are potent inhibitors of cytochrome P-450 metabolism. The influence of these flavonoids on the metabolism of 17 beta-estradiol was investigated in a microsome preparation from human liver. The flavonoids were added in concentrations of 10, 50, 100, 250 and 500 mumol/l to the microsome preparation. The metabolism of 17 beta-estradiol was concentration dependently inhibited by all the flavonoids tested. Addition of the flavonoids to the microsome preparation did not influence estrone formation, while a potent inhibition of estriol formation was observed. At the highest concentrations tested of the respective flavonoid, there was approximately 75-85% inhibition of estriol formation. However, naringenin was a less potent inhibitor of 17 beta-estradiol metabolism as compared to quercetin and kaempferol. The most likely mechanism of action of the flavonoids on 17 beta-estradiol metabolism is inhibition of the cytochrome P-450 IIIA4 enzyme, which catalyzes the reversible hydroxylation of 17 beta-estradiol into estrone and further into estriol. These hydroxylation processes represent the predominant steps of the hepatic metabolic conversion of endogenous as well as exogenous 17 beta-estradiol. This interaction would be expected to inhibit the first-pass metabolism of 17 beta-estradiol, and this has recently been demonstrated after oral administration of 17 beta-estradiol to women.

Factors affecting the yeild of urinary estriol.

PIP: Technical and maternal factors known to affect urinary estriol level or its measurement are discussed in view of the current use of serial estriol as an indicator of fetoplacental function. Technical artifacts can result from presence of methenamine mandelate, phenolphthalein, glucose, or high urine specific gravity. Aside from normal maternal factors such as inaccurate urine collection or variable fluid intake, estriol levels are depressed by corticosteroids and ampicillin. Pyelone phritis, anemia, hemoglobinopathy, abnormal renal status, malnutrition, and high altitude all depress estriol level or excretion. In some conditions such as pyelonephritis, amniotic estriol level may be a better indicator of fetal status.^ieng