What causes sudden infant death syndrome?

Some sudden infant death syndrome babies are born with brain abnormalities that make them vulnerable to sudden death during infancy. Studies of sudden infant death syndrome victims show that many sudden infant death syndrome babies have abnormalities in the "arcuate nucleus," a part of the brain that probably helps control breathing and waking during sleep. Babies born with defects in other portions of the brain or body may also be more prone to a sudden death. These abnormalities may result from exposure of the fetus to a toxic substance, or a decrease in oxygen. Cigarette smoking during pregnancy, for example, can reduce the amount of oxygen the fetus receives.

Some babies who die suddenly may be born with a metabolic disorder. One such disorder is medium chain acyl-CoA dehydrogenase deficiency, which prevents the baby from properly processing fatty acids. A build up of these acid metabolites could eventually lead to a rapid and fatal interruption in breathing and heart functioning. If there is a family history of this disorder or childhood death of unknown cause, genetic screening of the parents by a blood test can determine if they are carriers of this disorder. If one or both parents is found to be a carrier, the baby can be tested soon after birth.

Events such as lack of oxygen, excessive carbon dioxide intake, overheating, or an infection may be related to sudden infant death syndrome. Examples of a lack of oxygen and excessive carbon dioxide levels may include respiratory infections that cause breathing problems and rebreathing exhaled air trapped in underlying bedding when babies sleep on their stomachs.

More information on sudden infant death syndrome (SIDS)