Estradiol, estrone, and gonadotropin levels after use of vaginal estradiol.
Level 4 - case-series / case-control
Uncontrolled prospective pharmacokinetic study
What was done
Postmenopausal women received 0.5-mg tablets of micronized estradiol vaginally to evaluate systemic absorption. Serum estradiol, estrone, luteinizing hormone, and follicle-stimulating hormone were measured one hour after a single dose, and serum estradiol and estrone were measured 12 hours after insertion during a three-week alternate-day regimen.
What was found
One hour after a single dose, mean serum estradiol increased 5.3-fold and mean estrone increased 1.5-fold, with significant depression of mean luteinizing hormone and follicle-stimulating hormone levels (exact baseline and post-treatment concentrations were not reported). During the three-week alternate-day regimen, mean serum estradiol was consistently two to three times higher than estrone 12 hours post-dose.
Why it matters
Vaginal administration of micronized estradiol achieves rapid systemic absorption while maintaining a higher estradiol-to-estrone ratio than typical oral administration, reducing first-pass hepatic conversion.
Limits
The abstract does not report the sample size, baseline participant characteristics, absolute numerical hormone values, or variance metrics. The study lacked a concurrent randomized control group and followed participants for only three weeks.
Cited by
- supports Intravaginally administered medications such as estradiol are rapidly absorbed through vaginal tissue and can be measured in the bloodstream within minutes.