Impact of pregnancy on voice: a prospective observational study.

Purpose: We aimed to assess if there is a significant change in voice of pregnant women by the end of third trimester.

Materials and methods: Forty-nine pregnant women were enrolled in this study between April 2019 and March 2020. Subjective and objective voice evaluation was conducted in the third trimester and three months after delivery. The Turkish version of the VHI-10 questionnaire was filled out by every participant. GRBAS scale was used for perceptual voice evaluation. Acoustic analyses were conducted by Multi-Dimensional Voice Program (MDVP) (Computerized Speech Lab, Kay Elemetrics Corporation, Lincoln Park, NJ). Fundamental frequency (fo), Jitter percent (Jitt), Shimmer percent (Shim), noise to harmonic ratio (NHR), maximum phonation time (MPT), voice turbulence index (VTI), vocal intensity, and scale parameters were categorized as predelivery (a) and postdelivery (b).

Results: Comparison of acoustic parameters of the third trimester with the third month postpartum revealed statistically significant increases for fo (p = .013), MPT (p = .008), and vocal intensity (p≤.001) as well as a significant decrease for VTI (p≤ .001). No statistically significant difference was found for NHR, Jitt, and Shim. Comparison of both VHI-10 and GRBAS scores revealed statistically significant decreases.

Conclusions: Disturbances in certain vocal parameters suggest that vocal abnormalities observed during pregnancy are mainly due to anatomical alterations of the lower respiratory system. It would be appropriate to warn pregnant women about bad vocal habits and vocal hygiene. In addition, it would be appropriate to recommend professional voice support to pregnant women who use their voices intensively due to their profession.