A new study suggests a link between multiple pregnancies and hearing loss, and that the contraceptive pill appears protective against impaired hearing.
Researchers from China said previous studies suggested reproductive factors may influence women’s auditory health but the specific association between the number of pregnancies and auditory function remained inadequately understood.
They conducted a cross-sectional analysis of 5,269 American women aged 20 years and older (average age 46) from the National Health and Nutrition Examination Survey (NHANES) 1999–2018 data.
Among these participants, 624 (9.81%) had hearing loss.
Reproductive health data, including number of pregnancies, was obtained via self-reported questionnaires. Hearing loss was defined as a pure-tone average ≥ 25 dB HL at speech frequencies (0.5, 1, 2, and 4 kHz) in the better-hearing ear.
After adjusting for confounders, they found the number of pregnancies was significantly associated with hearing loss. Conversely, the use of birth control pills was associated with lower odds of hearing loss.
“Our findings demonstrated that a higher number of pregnancies was significantly associated with hearing loss, while birth control pill use appeared protective,” they said in BMC Public Health on 22 May 2025.
“Based on this finding, we provide the first evidence that, among US women, a higher number of pregnancies is independently associated with hearing loss.
“Meanwhile, we identified a protective effect of birth control pill use, as women who used birth control pills were significantly less likely to experience hearing impairment.”
Similar associations were observed in elderly women, where a higher number of pregnancies was linked to age-related hearing loss.
Hormonal changes a possible mechanism
The researchers, from the Department of Otolaryngology, Sun-Yat Sen Memorial Hospital, Guangzhou, Guangdong, said hormonal changes associated with pregnancy may contribute to hearing loss.
“Fluctuations in oestrogen levels during pregnancy can impact auditory function by interacting with the spiral ganglion’s oestrogen receptor α and the stria vascularis’s oestrogen receptor β, both of which are critical for auditory transmission and inner ear homeostasis,” they said.
“Additionally, oestrogen may modulate auditory function at multiple levels of the central nervous system by influencing the glutamatergic and GABAergic systems.”
Three previous studies had suggested that birth control pills have no significant effect on hearing function or otological diseases.
“Previous research predominantly involved younger women who had recently used birth control pills, focusing on short-term, direct effects on hearing function,” they said.
“In contrast, our study investigated the potential long-term, indirect association of birth control pill use with hearing loss, indicating that the observed association may be mediated by a lower cumulative number of pregnancies over a woman’s lifetime.”
The researchers said the findings highlighted the importance of recognising potential auditory health implications associated with multiple pregnancies and may inform future public health strategies aimed at supporting women’s hearing health across the reproductive lifespan.
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