Effect of Soy Isoflavone on Hot Flushes, Endometrial Thickness, and Breast Clinical as well as Sonographic Features

Background: Phytoestrogens treatment to relieve hot flushes in menopausal women was considered recently. However, the actual effectiveness and safety are not clear. Methods: Randomized clinical trial (IRCT#20100706004329N5) was performed in 204 patients who com-plained of hot flushes in Arash Women's Hospital, Tehran, Iran from 2013-2015. The first group received 50 mg isoflavone (group A) once daily and the second group received placebo (group B) in the same regimen. Pa-tients were evaluated for breast examination (BE) and breast sonography (BS) as well as vaginal sonography at initial presentation and at 6th and 12th week follow-ups. Patients were educated to record frequency and se-verity of hot flushes. Results: Group A experienced less hot flushes attack (6 vs 9 patients with 5< attacks in 6 wk (P= 0.05), 7 Vs 13 patients with 5< in 12 wk (P=0.01)) which was also less severe (8 vs 12 patients with severe symptoms in 6 wk (0.04) and 3 Vs 10 patients with severe symptoms in 12 wk (0.001). Isoflavone had no effect on neither breast density nor nodularity (in 6 wk, P=0.50 and 0.80, respectively and in 12 wk, P=0.32 and 0.43) and nei-ther breast tenderness nor nipple discharge (in 6 wk, P=0.40 and 0.34 respectively and in 12 wk, P= 0.31 and 0.26). There were no significant differences in endometrial thickness in 6 and 12wk. Conclusion: Effects of isoflavone on frequency and severity of hot flushes in perimenopausal women is ob-served. Some clinical and ultrasonographic benign non-significant changes of the breast and endometrium are noted after isoflavone intake.