A review of studies has suggested that hearing loss is more prevalent in newborns whose mothers have gestational diabetes mellitus (GDM) than babies whose mothers do not have GDM.
Overall, findings from auditory brainstem response (ABR) and otoacoustic emissions suggested auditory functioning may be impaired due to GDM, researchers said.
Their systematic review aimed to study the effect of GDM on the hearing acuity of newborns. Researchers from India looked at 425 studies and included seven in their review.
Results highlighted that GDM may affect the hearing sensitivity of newborns, they said.
“Findings suggest that hearing loss is more prevalent in newborns with GDM pregnancies than in non-GDM pregnancies,” they concluded.
“In addition, otoacoustic emissions (OAE) findings were ‘referred during the first hearing screening of newborns with GDM pregnancies.’ The refer rate of the first bilateral hearing screening was higher for newborns with GDM pregnancies.
“Furthermore, children of diabetic pregnancies were found to be at risk of bilateral hearing loss, particularly sensorineural in nature.”
The authors were Komal Aggarwal from the Department of Audiology and Speech-Language Pathology at Amity Medical School and Dr Rohit Ravi from the Department of Audiology and Speech Language Pathology, Kasturba Medical College, India.
They said globally, about one in seven pregnant women had gestational diabetes. The effect of GDM on the hearing sensitivity of newborns was unclear and their study aimed to explore this effect.
“The objective of this article is to bring attention to the possibility of hearing loss in newborns with GDM, encouraging clinicians to consider detailed audiological evaluations as part of the comprehensive care for these cases,” the researchers wrote in the Annals of Otology, Rhinology and Laryngology.
The studies observed significant failure of newborn hearing screening. This was evidenced by abnormal findings of otoacoustic emissions and auditory brainstem responses indicating that newborns with GDM pregnancies may have reduced or abnormal hearing acuity.
“Hearing evaluation should be mandated in newborns with GDM pregnancies to detect hearing loss at the initial stage. In addition, there is an alarming need for longitudinal studies with larger sample sizes to establish a definitive conclusion,” they said.
Additionally, healthcare professionals including gynaecologists, paediatricians and audiologists should be aware of this correlation as they could parents and family members about the importance of newborn hearing screening in GDM cases.
This multidisciplinary collaboration could smoothen early detection of hearing loss in newborns with GDM pregnancies, leading to early intervention and better clinical outcomes to improve quality of life of affected newborns, they added.
Two studies estimated prevalence of hearing loss in children of diabetic pregnancies. In one, almost 71% of children from diabetic pregnancies ‘demonstrated evidence of hearing loss’, compared to 45% in children of non-diabetic pregnancies.
It concluded: “Children of diabetic pregnancies face increased risks of developing HL, particularly bilateral and sensorineural hearing loss.”
Seven times higher
The second study concluded ‘prevalence of deafness in neonates of mothers with diabetes mellitus was 4.16%, which is about seven times higher than the prevalence of deafness in neonates without any risk factors.’
Other studies reported that poor gestational glycaemic control could cause vascular damage in the developing inner ear and another suggested increased insulin-like growth factor-1 could modify cochlear morphogenesis.
“Children with diabetic pregnancies were more likely to have high-frequency hearing loss with a severity of moderate to profound and sensorineural in nature,” the reviewers said. “These conjectures indicate that children with GDM pregnancies may have impaired hearing sensitivity.”
The other five studies included in the review evaluated hearing loss in newborns by administrating otoacoustic emissions (DPOAEs and TEOAEs) and auditory brainstem response. All found a higher failure rate of newborn hearing screening in newborns with GDM pregnancies.
Inadequate blood glucose levels during pregnancy could have harmful effects on pregnancy outcomes, researchers said.
A previous study examined the mechanism of oxidative stress and suggested hyperglycemia-induced oxidative stress could interfere with proteins, fats, and deoxyribonucleic acids, causing cell damage and inaccurate organogenesis.
“It has been revealed that GDM may result in sensorineural hearing loss in newborns because of immunological mechanisms, microcirculation, and ischemia. The earlier studies highlighted GDM as a risk factor for poor newborn hearing screening results,” they said.
“GDM pregnancies enhance the risk of respiratory distress, hyperbilirubinemia and metabolic disorders in newborns. Thus, it is essential to consider this alliance as an alarm to conduct hearing screening in newborns with GDM pregnancies.”