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MIDVALE -- Boston researchers published a study that shows SIDS babies have decreased levels of serotonin in their brain stems. This could lead to a biological basis for placing babies on their backs in bed.
Sudden Infant Death Syndrome, or SIDS, is the leading cause of unexpected death in babies 1 month to 1 year old. A new study discovered decreased levels of a critical chemical in the brain stems of SIDS babies.
KSL talked with pediatrician Dr. Jeffrey Cline at Greenwood Health Center in Midvale as he was checking little Zoe Bradbury. Zoe is a happy, healthy 9-month-old baby. But, too many of her peers will not survive infancy because of Sudden Infant Death Syndrome.
Dr. Cline has not read the study, but he's eager to hear about promising research.
"I don't think anybody has classified exactly what the underlying circumstances are that lead to SIDS. So, that is the first fundamental step in identifying the problem before you can work towards treating it," Dr. Cline says.
"We found that the babies who died of SIDS had abnormalities in serotonin in regions of the brain stem that control breathing and heart rate and blood pressure during sleep," Dr. Kinney says.
The researchers suggest that if a baby is put face down in the bed, it begins to re-breathe toxic carbon dioxide. A normal baby could lift its head and wake up. But, a baby with a defect in brain stem circuits that use serotonin cannot do that, and dies.
"So, if you have a deficiency in these serotonin pathways that regulate vital functions during sleep and in response to challenges, an infant may go on to die during sleep," says Dr. Kinney.
Dr. Kinney and co-authors reviewed autopsies of SIDS babies and babies who died from known causes. The study appears in Journal of the American Medical Association. It shows SIDS babies had lower levels of serotonin and related chemicals in their brain stems. There was a 26 percent decrease in the level of serotonin and a 22 percent decrease in the level of tryptophan hydroxylase, the enzyme that makes serotonin. Also, they showed more than 50 percent decreases in receptors in different regions of the medulla of the brain stem.
"SIDS doesn't really give us that," says Cline. "It says that we don't really know. We've looked at a lot of other reasons, and we still aren't able to tell you exactly what happened to your child. It's very frustrating."
Dr. Cline says regulating serotonin in babies would be a very distant step, even if the cause were conclusive.
Researchers say the study findings may give a biological basis for infants to be put to sleep on their backs. That's what pediatricians recommend.
If you're concerned about SIDS risk factors, talk to your pediatrician.
E-mail: jboal@ksl.com
