Objective: To determine if intercourse changed serum estradiol levels in women using vaginal E2 cream or in their male partners.
Study design: Prospective, randomized, placebo-controlled, crossover, blinded study of 10 postmenopausal women and their male sexual partners. Subjects were randomized to estradiol or placebo cream and intercourse, then crossed over after 7-14 days. Seven to 14 days later, the woman used vaginal estradiol cream and abstained from intercourse. Serum E2 levels were obtained 10-12 hours after each exposure.
Results: Serum E2 levels were higher in 8 of 10 men after intercourse with vaginal estradiol cream, and this resulted in a small but significant (p = 0.03) increase in the estradiol levels as compared to placebo. Paradoxically, intercourse resulted in markedly lower estradiol levels in women as compared to abstinence (p = 0.004).
Conclusion: Men absorb vaginal estradiol during intercourse, whereas intercourse reduces estradiol absorption in women. Although serum estradiol levels were only mildly elevated in men, it is possible that long-term exposure could cause feminizing changes. In women, estradiol levels were markedly reduced by intercourse.