The 42-day hearing screening is a common clinical method of determining the hearing of newborns. It is performed during the child’s natural sleep state through electrophysiologic tests such as otoacoustic emissions, autoacoustic brainstem response, and acoustic impedance to detect the presence of hearing impairment in newborns. The accuracy of the 42-day hearing screen is about 30%, and is influenced by a number of factors. It is necessary to combine two hearing screenings, one at 3 months and the other at 6 months, to determine whether the child’s hearing is abnormal. Most babies who do not pass the hearing screening test do not have a definite hearing loss after the diagnostic hearing test. The reason for this is that the existing secretions in the outer or middle ear canal (retained fetal fat and amniotic fluid in the outer ear canal; and fluid in the middle ear cavity) have been absorbed or discharged. When conducting hearing screening, the best test results are obtained when the baby is in a natural sleep state. Test results can be affected when the baby is restless, crying or has an unventilated nose. Therefore, babies need to be quiet and sleepy when they undergo hearing screening, preferably about half an hour after they have eaten, and parents can stroke their babies to try to calm them down if necessary. If your baby is diagnosed with hearing impairment, early intervention is recommended.