by Amy Spangler
February 09, 2010

Although the incidence of Sudden Infant Death Syndrome (SIDS) decreased significantly after the launch of the Back to Sleep campaign in 1994, SIDS is still the leading cause of death in children 1 month to 1 year of age. While the cause of SIDS remains a mystery, researchers recently identified a defect in the brain of infants who died of SIDS that may eventually lead to early detection of babies at risk for SIDS.

Published in the February 3, 2010 issue of the Journal of the American Medical Association (JAMA), researchers compared the brainstems of 41 infants who died of SIDS with seven infants who died from known causes and five infants who were hospitalized with poor low oxygen levels before they died. The brainstem controls heart rate, breathing, body temperature, and blood pressure which are key factors in sleeping and waking.

Researchers found that 35 of the 41 infants who died of SIDS had low levels of serotonin, a chemical that transmits messages between cells and regulates breathing, heart rate, and sleep. Compared to the serotonin levels in the 12 infants who had died from other known causes, levels in infants who died from SIDS were 26 percent lower. In addition, the level of tryptophan hydroxylase, an enzyme needed to make serotonin, was 22 percent lower in infants who died from SIDS.

Dr. Hannah Kinney and her colleagues had previously reported differences in serotonin levels in infants who had died from SIDS compared to those who had not, but it was unclear then whether the SIDS babies had too little or too much serotonin.

Recommendations
Understanding how an infant dies from SIDS is the first step toward preventing SIDS. While these latest findings are compelling, SIDS prevention based on biological testing is years away. In the meantime, parents should continue to focus on taking actions that have been shown to reduce the risk for SIDS.

1. Always place your baby on his or her back to sleep—babies who sleep on their backs are less likely to die of SIDS than babies who sleep on their stomachs or sides.
2. Remove soft, fluffy, or loose bedding and toys from your baby’s sleep area—use only a lightweight cover or blanket, or place your baby in a sleep sack. Do not use pillows, comforters, quilts, duvets, or bumper pads in your baby’s sleep area.
3. Do not let your baby get too hot—dress your baby in a single layer of clothing or a sleep sack. Keep the room at a temperature that is comfortable for adults.
4. Place your baby on a firm sleep surface—never place your baby to sleep on a soft mattress, waterbed, sofa, or chair.
5. Offer a pacifier when putting your baby to sleep—if your baby refuses a pacifier, do not force him or her to take it. Many babies prefer to suck on fingers and fists. Mothers who are breastfeeding should wait until their baby is breastfeeding well (about 1 month of age) before offering a pacifier.