Sixth International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA 2009)
During pregnancy significant changes in bodily tissues occur. For example, the cervix undergoes deep structural/biomechanical alterations due to an increase in concentration of progesterone. Previous studies have found a significant correlation between the changes that both cervical and vocal fold smears undergo during the menstrual cycle, demonstrating a relevant hormonal influence on laryngeal tissues. It can be hypothesised that such tissue changes that may occur during pregnancy affect conditions for phonation with respect to e.g. vocal fold motility. To test this hypothesis recordings of audio, electrolaryngograph, oral pressure and air flow signals were made during pregnancy, at birth and after pregnancy of a semi-professional classically trained soprano. The tasks involved repetitions of the syllable [pae] while performing a diminuendo at various pitches, thus allowing determination of the lowest pressures producing vocal fold vibration and vocal fold contact, i.e. the phonation and contact threshold pressures. Oral pressure during the occlusion for the consonant [p] was accepted as a measure of subglottal pressure. Concentrations of sex female steroid hormones were measured during pregnancy, at birth and post-partum. Results showed a steep decrease of concentrations of progesterone and oestrogens from pregnancy to post-partum conditions. Likewise, phonation and collision thresholds decreased markedly at birth and post-partum, shifts that are in accordance with expectations based on the effects of sex steroid hormones on tissue viscosity and water retention. The results thus demonstrate an effect of pregnancy on the voice.
Full Paper (reprinted with permission from Firenze University Press)
Bibliographic reference. Lã, Filipa M. / Sundberg, Johan (2009): "Singing voice and pregnancy - preliminary results from a case study", In MAVEBA-2009, 171-174.