Oslo, Norway — A study conducted by Folkehelseinstituttet (the Norwegian Institute of Public Health) found a relationship between low birth weight and hearing loss. The risk of hearing loss is greatest in children weighing less than 3.3 pounds.

”The ears may not be fully developed due to slow growth in the uterus,” said Bo Engdahl, one of the scientists behind the study.

In the study, 327 children with sensorineural hearing loss were identified through the Norwegian county register in the period 1978-1998. These children were diagnosed with sensorineural hearing loss before they were five years old. The children with hearing loss were compared with all children without hearing loss in the same counties.

The risk of sensorineural hearing loss is reduced as the birth weight is increased. At birth weights above 7.7 pounds the risk is reportedly minimal.  The growth of the fetus during pregnancy, not the duration of the pregnancy, determines the hearing development, according to Engdahl.

Thus, the study points towards monitoring potential causes of slow growth of the fetus. These include disease or illnesses suffered by the mother, smoking, abusing drugs or suffering from infections.

SOURCE: Folkehelseinstituttet, March 2008; post modified from item found on www.hear-it.org.