High-Frequency TEOAE Amplitude Ratio Alterations in Newborns Exposed in Utero to Maternal SARS-CoV-2 Infection: A Prospective Cohort Study.

Background and

Objectives

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy has raised concerns regarding possible fetal consequences, including potential effects on auditory system development. Although the current literature suggests that overt congenital hearing loss is uncommon among newborns exposed in utero, subtle cochlear functional alterations may not be detectable through conventional threshold-based screening alone. The objective of this study is to investigate whether in utero exposure to maternal COVID-19 is associated with early cochlear functional changes in newborns, as assessed by frequency-specific transient evoked otoacoustic emission (TEOAE) amplitude ratios, and to determine whether such alterations are accompanied by differences in click-evoked auditory brainstem response (ABR) thresholds. Materials and

Methods

This prospective cohort study was conducted between October 2021 and September 2022 and included 61 pregnant women: 30 with laboratory-confirmed SARS-CoV-2 infection during pregnancy (study group) and 31 without documented infection (control group). All newborns underwent standardized audiological evaluation shortly after birth, including otoscopy, TEOAE, click-evoked ABR, and tympanometry. Frequency-specific TEOAE amplitude ratios at 500, 1000, 1500, 2000, and 4000 Hz were compared between groups. A logistic regression analysis was performed to identify audiological predictors of newborn exposure to SARS-CoV-2 in utero.

Results

No significant differences were observed in ABR thresholds or in TEOAE "pass/refer" outcomes between the control and study groups, indicating the absence of clinically overt HL. However, newborns exposed to SARS-CoV-2 in utero showed significantly reduced TEOAE amplitude ratios at 2000 Hz (p = 0.0077) and 4000 Hz (p = 0.020). Logistic regression identified the 4000 Hz amplitude ratio as an independent negative predictor of in utero exposure (OR = 0.75; p = 0.0352). No significant differences were detected at lower frequencies.

Conclusions

Maternal COVID-19 during pregnancy was not associated with immediate neonatal HL but was linked to subtle high-frequency cochlear functional modulation. Longitudinal audiological follow-up is needed to clarify the clinical significance of these findings.