Incidence and characteristics of sudden sensorineural hearing loss during pregnancy and the postpartum period: A nationwide population-based study using customized cohort data.

Objective: This study aimed to investigate the incidence and characteristics of sudden sensorineural hearing loss (SSNHL) in pregnant and non-pregnant women using the Korean National Health Insurance Service customized cohort data.

Methods: We defined the delivery group as women aged 15-49 years with International Classification of Diseases 10th Revision codes O80-O84 indicating delivery between January 2013 and December 2019. The control group was selected from individuals in the same age range without a history of delivery during the same period. SSNHL was defined as having an H91.2 diagnostic code and having undergone audiometry at least once. The incidence and characteristics of SSNHL were compared between the two groups from 2015 to 2018.

Results: The incidence of SSNHL per 1000 individuals was lower in the delivery group (1.08-1.17) compared to the control group (1.52-1.80) each year. In the delivery group, SSNHL occurred most frequently in the 30-34 age group during the third trimester of pregnancy and the postpartum period. The proportion of patients with SSNHL with comorbidities such as hypertension, diabetes, and dyslipidemia was higher in the delivery group than in the control group.

Conclusions: Using the longest follow-up period and the largest population in South Korea, we found that pregnancy and childbirth did not increase the risk of SSNHL, which is consistent with the results of previous population-based studies. Our findings provide insights into the etiology of SSNHL and highlight the need for further research to better understand the underlying mechanisms and risk factors associated with SSNHL.