Temporary conductive hearing loss can be caused by such things as a middle ear infection (otitis media) and from excess ear wax. Conductive hearing loss could also result from problems associated with the eardrum or with the bones of the middle ear.
Permanent sensori-neural hearing loss can be present at birth from genetic causes, from ototoxic drugs (drugs that damage hearing), from various other causes such as high bilirubin at birth, from inadequate oxygen at birth, and in slightly less than half of all children from unknown causes.
Permanent sensori-neural hearing loss can also result after birth from exposure to loud sounds, and also sometimes occurs as a result of meningitis in children.
There are some risk factors that predispose infants to late onset or progressive hearing loss: mechanical ventilation at birth, CMV, and certain genetic causes or syndromes.