Type of Resources
Several researchers have documented changes in auditory function throughout pregnancy (Kwatra et al., 2019; Sennaroglu & Belgin, 2001; Tandon et al., 1990). These studies, however, have not examined changes to otoacoustic emissions (OAEs). Otoacoustic emissions are an objective measure that have been shown to be more sensitive to differences in biological sex (Cassidy & Ditty, 2001; Dunckley & Dreisbach, 2004; Keogh et al., 2001; McFadden et al., 2006) and to changes in the female menstrual and ovarian cycles (Arruda & Monteiro de Castro Silva, 2008; Gurbuzler et al., 2012; Yellin & Stillman, 1999). The purpose of this study was to determine if auditory function up to and including the cochlea is affected by pregnancy. Auditory function was evaluated by comparing otoacoustic emissions data across multiple test sessions before, during, and after pregnancy. Two women with no reported history of thyroid disease or disorder or hearing loss as well as no recent use of hormonal birth control were followed across five separate testing sessions. The testing sessions occurred once before pregnancy, once per trimester, and once postpartum. Each test session included completion or updating of a relevant case history form, otoscopy, tympanometry, and measurement of distortion product otoacoustic emissions (DPOAEs) and transient evoked otoacoustic emissions (TEOAEs). Case history, otoscopy, and tympanometry were used to ensure there were no confounding variables related to outer/middle ear function, which would impact DPOAE and
TEOAE results. The dependent variables were DPOAE and TEOAE amplitude levels (dB SPL) and signal-to-noise ratio (SNR) levels (dB SPL) across several test frequencies. Amplitude and SNR levels were compared across test sessions and reported individually for each case. The results of this study showed minimal differences between test sessions for both amplitudes and SNRs of each subject. This could be due to otoacoustic emission testing not being sensitive enough to minute changes in the auditory system or due to the small sample size. A larger sample size of case studies would be beneficial to better identify the potential changes in the amplitudes and SNRs of DPOAEs and TEOAEs beginning, during, and after pregnancy.