Objective

To evaluate vaginal, endometrial, and reproductive hormone effects of three herbal regimens compared with placebo and hormone therapy (HT).

Design

This was a 1-year, randomized, double-blind, placebo-controlled trial of 351 women, ages 45 to 55, with two or more vasomotor symptoms per day. Women were randomly assigned to (1) black cohosh, (2) a multibotanical containing black cohosh, (3) the same multibotanical plus dietary soy counseling, (4) HT, or (5) placebo. Women were ineligible if they had used HT in the previous 3 months or menopausal herbal therapies in the previous month. Data on vaginal cytology and dryness were collected (at baseline and 3 and 12 mo). Daily menstrual diaries were maintained by 313 women with a uterus, and abnormal bleeding was evaluated. Serum estradiol, follicle-stimulating hormone, luteinizing hormone, and steroid hormone-binding globulin were assessed (baseline and 12 mo) among 133 postmenopausal women. Gynecologic outcomes of the five groups were compared.

Results

The five groups did not vary in baseline vaginal cytology profiles, vaginal dryness, menstrual cyclicity, or hormone profiles. The HT group had a lower percentage of parabasal cells and vaginal dryness than the placebo group at 3 and 12 months (P < 0.05). Abnormal bleeding occurred in 53 of 313 (16.9%) women. There were no differences in frequency of abnormal bleeding between any of the herbal and placebo groups, whereas women in the HT group had a greater risk than those in the placebo group (P < 0.001). Among postmenopausal women, HT significantly decreased follicle-stimulating hormone and increased estradiol; none of the herbal interventions showed significant effects on any outcomes at any time point.

Conclusion

Black cohosh, used alone or as part of a multibotanical product with or without soy dietary changes, had no effects on vaginal epithelium, endometrium, or reproductive hormones.