Auditory brainstem responses during menstrual cycle and pregnancy

The sexual hormones alter during menstrual cycle and pregnancy. Despite the physiological benefits of these changes, their adverse effects on hearing system such as hearing loss and vertigo have been reported. Therefore, in this study, the auditory brainstem responses (ABR) were investigated during physiological hormonal variations in the menstrual cycle as well as pregnancy. In this comparative-cross sectional research, the ABR was assessed in 25 women, including 17 pregnant and 8 non-pregnant women. The assessment was conducted at 24th week of pregnancy and in two stages of the menstrual cycle, on the 1st-3rd day and once again during the 12th-15th day in non-pregnant women (control group). Click stimuli ABR was recorded and compared between aforementioned groups. According to our results, ABR wave V absolute latency, III-V and I-V interpeak latencies were significantly longer during the 12th-15th day of menstrual cycle compared to 1st-3rd day results (p<0.05). These significant increases were observed between pregnant women and control groups (p<0.05). The research revealed the influence of hormonal changes during menstrual cycle and pregnancy on brainstem and auditory pathways. We concluded that the brainstem auditory pathways processing decelerates with the increase of estrogen and progesterone hormones.