Newborns

• Low birth weight (especially less than 3.3 pounds, or 1.5 kilograms)

• Low Apgar score (lower than 5 at 1 minute after birth or lower than 7 at 5 minutes after birth)

• Low blood oxygen levels or seizures resulting from a difficult delivery

• Infection before birth with rubella, syphilis, herpes, cytomegalovirus, or toxoplasmosis

• Abnormalities in the skull or face, especially those involving the outer ear and ear canal (see Developmental Abnormalities of the Outer Ear)

• A high level of bilirubin (a waste product) in the blood ( see Jaundice in the Newborn)

• Bacterial meningitis ( see Meningitis in Children)

• Bloodstream infection (sepsis)

• Use of a ventilator (a machine that helps air get in and out of the lungs) for a long time

• Use of certain drugs that can damage the ears, such as aminoglycoside antibiotics and some diuretics

• History of early hearing loss in a parent or close relative

Older children

All the above, plus the following:

• A head injury with a skull fracture or loss of consciousness

• Chronic middle ear infections or a cholesteatoma

• Some neurologic disorders, such as neurofibromatosis and neurodegenerative disorders (such as Hunter syndrome)

• Exposure to noise at high levels or for long periods

• Perforation of the eardrum due to infection or injury