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Introduction

Larynx is under the influence of sex hormones. In the life span of women, the dynamic change in the production of estrogens, progesterone, and androgens is dramatic. In each phase, that is, at puberty, in the reproductive years, and at menopause, the fluctuation in the concentration and distribution of sex hormones has an impact on voice. Each phase folds and unfolds different vocal characteristics. Being a secondary sexual characteristic, voice is affected by sexual maturation . At puberty, as a result of the increased secretions of gonadotropins and the arousal of the female hormonal system, the female voice reaches maturity. There is a drop in vocal pitch by one third, an increase in amplitude, and an increase in the perturbation parameters. These vocal changes during puberty have been attributed to the development of the laryngeal structures, namely, the thyroid cartilage and thyroarytenoid muscles, and to the development of the vocal tract. In males, the development is more accentuated and coupled with a downward descend of the larynx, resulting in lowering of the formants and a decrease in formant dispersion. All of which contribute to the further deepening of the voice witnessed in men and not in women .

During the reproductive years and throughout the menstrual cycle, vocal changes have also been reported in almost 33% of nonprofessional voice users. These have been attributed to edematous changes in the vocal folds and microvariceal dilatations . At menopause, the decrease in the production of estrogen and progesterone also results in vocal changes described often as loss of power, inability to sustain high notes, loss of flexibility and timbre, and reduction in voice stability . These subjective reports were supported later by more objective findings. Abitbol et al have described the vocal folds of menopausal women with dysphonia as being more atrophic and having thinner mucosa with the presence of microvarices. These findings explain the reduced vibratory amplitude and asymmetrical vibratory pattern often witnessed in these patients.

Hence, the fluctuations in the estrogen and progesterone levels during the reproductive years seem to be responsible for the women’s vocal characteristics throughout the menstrual cycle, whereas the decrease in estrogen and progesterone levels at menopause seem to induce mucosal and muscular atrophy, together with degradation of connective tissues, all of which result in changes in voice quality witnessed in menopausal women. Thus vocal characteristics associated with normal and or reduced estrogen levels have been described, but there are no reports on vocal changes in relation to elevated estrogen levels. Women undergoing in vitro fertilization (IVF) are subjected to marked hormonal suppression and, later, stimulation, that is, in estrogen, the effect of which on voice has not been reported.

Based on PubMed search using the words “In Vitro Fertilization” and “Voice,” we could not identify a study that has investigated the vocal changes in women during IVF. Knowing the marked influence of the sex hormones on the laryngeal structures, the authors of this study elected to examine the incidence of vocal symptoms and their relation to variations in estrogen level in women undergoing IVF.