Pregnancy and the singing voice: reports from a case study.

OBJECTIVES

Significant changes in body tissues occur during pregnancy; however, literature concerning the effects of pregnancy on the voice is sparse, especially concerning the professional classically trained voice.

HYPOTHESES

Hormonal variations and associated bodily changes during pregnancy affect phonatory conditions, such as vocal fold motility and glottal adduction.

DESIGN

Longitudinal case study with a semiprofessional classically trained singer.

METHODS

Audio, electrolaryngograph, oral pressure, and air flow signals were recorded once a week during the last 12 weeks of pregnancy, 48 hours after birth and during the following consecutive 11 weeks. Vocal tasks included diminuendo sequences of the syllable /pae/ sung at various pitches, and performing a Lied. Phonation threshold pressures (PTPs) and collision threshold pressures (CTPs), normalized amplitude quotient (NAQ), alpha ratio, and the dominance of the voice source fundamental were determined. Concentrations of sex female steroid hormones were measured on three occasions. A listening test of timbral brightness and vocal fatigue was carried out.

RESULTS

Results demonstrated significantly elevated concentrations of estrogen and progesterone during pregnancy, which were considerably reduced after birth. During pregnancy, CTPs and PTPs were high; and NAQ, alpha ratio, and dominance of the voice source fundamental suggested elevated glottal adduction. In addition, a perceptible decrease of vocal brightness was noted.

CONCLUSIONS

The elevated CTPs and PTPs during pregnancy suggest reduced vocal fold motility and increased glottal adduction. These changes are compatible with expected effects of elevated concentrations of estrogen and progesterone on tissue viscosity and water retention.