The Effects of Hormone Replacement Therapy on Vocal Fundamental Frequency in Postmenopausal Women

To explore differences in vocal fundamental frequency (F0) between premenopausal and postmenopausal women through associations with age and hormone use, including estrogen-progesterone therapy with testosterone replacement (EPT-HRT) and birth control (BC).

This cross-sectional, multi-institutional study recruited four groups: postmenopausal women taking EPT-HRT, postmenopausal women not taking HRT (HRT-naïve), premenopausal women taking BC, and premenopausal women not taking BC (hormone-naïve). The primary outcome was F0 in Hertz (Hz), compared between groups as a difference (Δ) with 95% confidence interval (CI) and correlated (r) with demographic variables.

Ninety-six participants were recruited, with 24 per group: postmenopausal women on EPT-HRT (mean age:51; range:32-65), HRT-naïve postmenopausal women (60 [49-74]), premenopausal women on BC (26 [23-30]), and hormone-naïve premenopausal women (29 [22-45]). There was no significant difference in F0 between postmenopausal women with (174 ± 14 Hz) and without EPT-HRT (173 ± 20Hz) (P = 0.91) or premenopausal women with (198 ± 24 Hz) and without BC (191 ± 20 Hz) (P = 0.19). Mean F0 of postmenopausal women on EPT-HRT was lower than in both premenopausal women on BC (Δ24.3 [CI: 13.6-35.7]; P < 0.0001) and not on BC (Δ16.7[CI: 5.3-28.1]; P = 0.005). A moderate negative correlation was observed between age and F0 (r = -0.39; P < 0.001).

This study found that F0 decreases with age in women, with no significant effect from testosterone-containing HRT.