This article originally appeared in the Feb. 24, 2010 edition of the St. Louis Post-Dispatch.
New evidence has been reported this month, pointing to another possible link to Sudden Infant Death Syndrome (SIDS). Researchers say SIDS may be associated with low brainstem levels of serotonin, a compound that helps regulate some of the body’s involuntary actions, such as breathing, heart rate and blood pressure during sleep.
Sudden infant death affects about 4,000 babies each year in the U.S. About 100 babies in Missouri and nearly that many in Illinois die each year from SIDS.
Over two decades, researchers at Children’s Hospital Boston have investigated the possible causes of SIDS. In the newly released research, babies who had succumbed to SIDS had 25 percent less serotonin in their lower brainstem and 22 percent lower levels of tryptophan hydroxylase, the enzyme that makes serotonin.
“The factor or factors that lead to SIDS deaths are still unknown, but this research indicates that low serotonin levels may be a risk factor,” says Dr. Shalini Paruthi, director of the Pediatric Sleep and Research Center at SSM Cardinal Glennon Children’s Medical Center, who is board-certified in sleep medicine. She also is assistant professor of pediatrics at Saint Louis University School of Medicine. “Other risk factors include tummy or side-sleeping, sharing a sleep surface with another child or adult, too much bedding, overheating, soft objects in the crib, smoke in the child’s environment, and sleep deprivation.”
According to another study published in last week’s issue of Pediatrics, babies affected by SIDS commonly have two or more of these risk factors. SIDS-related deaths are rare when one or none of these factors is present.
Lori Behrens, executive director of St. Louis-based SIDS Resources, agrees that recent research findings re-emphasize the importance of safe sleep and other infant safety.
“Since we do not have a screening test yet for low serotonin, we must assume all babies are potentially at risk,” Behrens said.
For vulnerable babies or those with low serotonin levels, re-breathing carbon dioxide (exhaled air) and overheating during sleep can be fatal. Parents need to do all they can to make sure their baby is always placed to sleep on his or her back and in a safe place.
Safe sleep recommendations include:
- Follow the ABC’s of safe sleep for your baby: Babies must always sleep Alone, on their Backs, in their Cribs (for night time and nap time). Babies should not be exposed to cigarette smoke.
- Make sure the crib mattress is firm.
- There should be no soft items, including bumper pads, pillows and stuffed animals, in the crib.
- Breastfeed your baby.
- Room sharing is good, however babies should never share a sleep surface or sleep area with any other child or adult. Using pacifiers during sleep has shown to be protective against sudden infant death.
For more information on SIDS, visit the SIDS Resources Web site at
Dr. Bob Wilmott is Chief of Pediatrics at SSM Cardinal Glennon Children’s Medical Center and is a Professor of Pediatric Medicine at Saint Louis University School of Medicine. If you have a question about your child’s health, go to the “Ask Dr. Bob” section of the Cardinal Glennon Web site at www.cardinalglennon.com.