A study published in Journal of the American Medical Association Boston shows that SIDS (Sudden Infant Death Syndrome) babies have lesser levels of serotonin in their brain stems. This study supports the tradition of placing babies on their backs in the bed. Serotonin basically is a neurotransmitter that helps control breathing, blood pressure and heart rate in the brain during sleep.

Dr. Hannah Kinney of Children's Hospital Boston along with other researchers said, "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. 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".

According to the research if a baby is put face down in the bed, it begins to re-breathe toxic carbon dioxide. A normal baby could elevate its head and wake up. But a baby with less serotonin cannot do that, and can die. This research is expected to help doctors develop some screening tests for detection of SIDS in babies which is a reason for a number of sudden infant deaths.