Prenatal stress is important to study, due to research findings that suggest stress levels are associated with negative consequences in fetal and infant development. (1) The relationship between exposure to prenatal stress with increased reactivity to stress and cognitive problems in adulthood, indicating that the stress can effect on person at different periods of life.(3,4p+ nature)
Stress has high prevalence during pregnancy .(2) When a person is exposed to stressful events , the brain triggers a cascade of events ultimately leading to the release of stress hormones, such as glucocorticoids .(3) A portion of these glucocorticoids that transmit to the fetus through the placenta, increasing fetal HPA axis activity and changing brain development.( …show more content…
(1,11-12). It was revealed that exposure to high levels of glucocorticoids during fetal period result in differentiation of inner ear tissues with fewer blood vessels and progenitor cells (11). This condition, in turn, will damage the cochlea (11) and increases hearing threshold (9). Furthermore, in these animals, vulnerability to ototoxic agents will be increased. (13). Conflict at The higher levels of afferent auditory pathways is also seen in animals with a history of embryonic stress (13). Impaired sensory gating (14), severe startle reflex (15), dendritic atrophy of auditory cortex (16), atrophy of auditory neurons in Inferior Colliculus (17) and neuronal morphology defects in different parts of CANS (central auditory nervous system) (17) can be mentioned as another consequences of fetal stress. It was also reported that stress can affect cochlear function at the molecular level (17) which results in sudden hearing loss (SHL) (18), tinnitus and dizziness (19) and hyperacusis (17). However, the effect of exposure to high levels of stress during fetal period or high levels of synthetic glucocorticoids during pregnancy on cochlea and hearing threshold has not been confirmed in all studies (1, 13) and more researches are needed in this
Stress has high prevalence during pregnancy .(2) When a person is exposed to stressful events , the brain triggers a cascade of events ultimately leading to the release of stress hormones, such as glucocorticoids .(3) A portion of these glucocorticoids that transmit to the fetus through the placenta, increasing fetal HPA axis activity and changing brain development.( …show more content…
(1,11-12). It was revealed that exposure to high levels of glucocorticoids during fetal period result in differentiation of inner ear tissues with fewer blood vessels and progenitor cells (11). This condition, in turn, will damage the cochlea (11) and increases hearing threshold (9). Furthermore, in these animals, vulnerability to ototoxic agents will be increased. (13). Conflict at The higher levels of afferent auditory pathways is also seen in animals with a history of embryonic stress (13). Impaired sensory gating (14), severe startle reflex (15), dendritic atrophy of auditory cortex (16), atrophy of auditory neurons in Inferior Colliculus (17) and neuronal morphology defects in different parts of CANS (central auditory nervous system) (17) can be mentioned as another consequences of fetal stress. It was also reported that stress can affect cochlear function at the molecular level (17) which results in sudden hearing loss (SHL) (18), tinnitus and dizziness (19) and hyperacusis (17). However, the effect of exposure to high levels of stress during fetal period or high levels of synthetic glucocorticoids during pregnancy on cochlea and hearing threshold has not been confirmed in all studies (1, 13) and more researches are needed in this