Maternal oral glucose tolerance test parameters and neonatal hearing screening outcomes: a retrospective cohort study.

Abstract

Background: Gestational diabetes mellitus (GDM) has been associated with adverse pregnancy outcomes and may influence fetal neurosensory development, particularly auditory function. However, evidence regarding its effect on neonatal hearing screening remains inconsistent.

Objectives: To evaluate the association between maternal Oral Glucose Tolerance Test (OGTT) glucose levels (fasting, 60-minute, and 120-minute) and neonatal hearing screening outcomes, and to explore whether maternal glycemic status, including GDM, affects early auditory function in newborns.

Design: Retrospective observational study.

Setting: Tertiary university hospital (Izmir University of Economics Medical Point Hospital) between 2015 and 2024.

Patients (materials) and methods: Singleton pregnancies with available 75-g OGTT data and corresponding neonatal hearing screening results were included. Maternal glucose levels (fasting, 60-, and 120-minute) were analyzed according to hearing screening outcomes (pass or refer). Non-parametric tests were applied.

Main outcome measures: Failure in neonatal hearing screening and its association with maternal OGTT parameters.

Sample size: A total of 463 mother-newborn pairs were included.

Results: Sixty-minute OGTT glucose levels differed significantly across hearing screening outcome groups (P=.003). Mothers of infants with bilateral hearing screening failure had significantly higher 60-minute glucose levels compared to those whose infants passed (P=.004). No significant associations were observed for fasting or 120-minute glucose levels. In multivariable logistic regression analysis, no independent association was identified between maternal OGTT parameters and hearing screening failure after adjustment for mode of delivery and parity. Additionally, no significant associations were found between OGTT values and neonatal anthropometric measurements.

Conclusions: Elevated postprandial glucose levels may be associated with early alterations in neonatal hearing screening results; however, maternal glucose parameters were not significantly associated with hearing screening failure. These findings suggest that observed abnormalities may reflect transient functional changes rather than permanent auditory impairment.

Limitations: Retrospective design, lack of confirmatory auditory brainstem response testing in all cases, and potential influence of unmeasured neonatal and perinatal confounders.