Effects of Glycine max (L.) Merr. soy isoflavone vaginal gel on epithelium morphology and estrogen receptor expression in postmenopausal women: a 12-week, randomized, double-blind, placebo-controlled trial.

OBJECTIVE: Evaluate the effects of vaginal administration of isoflavones derived from Glycine max (L.) Merr. as a treatment option for vaginal atrophy, on the morphology and expression of estrogen receptors in vaginal epithelium of postmenopausal women.

METHODS: The double-blind, randomized, placebo-controlled, clinical trial. Sixty women were treated for 12 weeks with isoflavone vaginal gel 4% (1g/day) and a placebo gel. After 4 and 12 weeks, the vaginal atrophy symptoms were classified at none, mild, moderate and severe and the vaginal cytology were taken to determine the maturation value. Vaginal pH was measured at the beginning and end of therapy. Microbiopsies in vaginal fornix were performed before the treatment and after 12 weeks of treatment.

RESULTS: Isoflavone vaginal gel was effective for relief of vaginal dryness and dyspareunia symptons and an increase in the intermediate and superficial cells was noted. The vaginal pH in the isoflavone group was 7.1 at baseline and 5.4 after 12 weeks, whereas in the placebo group there was no significant change. A significant increase in thickness after treatment was detected in the Isoflavone Group. The percentage of estrogen receptor positive cells in vaginal epithelium for the Isoflavone Group ranged from 58.5% at the beginning of treatment to 82.6% after 12 weeks. These results were superior to placebo gel.

CONCLUSION: Glycine max (L.) Merr. at 4% vaginal gel on a daily basis in postmenopausal women led to improvements in vaginal atrophy symptoms, maturation values, vaginal pH, morphology and expression of estrogen receptors in vaginal epithelium. Isoflavones proved good treatment options for relief of vulvovaginal atrophy.