A 3-month-old baby who fails hearing screening in both ears may be related to congenital deafness, etc. The cause should be identified and treated as soon as possible. Under normal circumstances, the baby’s hearing is already quite good at 3~7 days after birth, and at 3~4 months the head can be turned towards the sound source and smile when hearing pleasant sounds. If your baby fails the hearing screening in both ears at 3 months of age, and usually has no or less response to sound than his/her peers, you may suspect congenital deafness or nerve damage as the cause. It is recommended to find out the cause as soon as possible because the development of auditory perception is directly related to language development, and if the baby’s hearing impairment cannot be diagnosed and intervened within 6 months, he/she may become mute as a result of deafness.