Sudden Infant Death syndrome (SIDS) may be one of the most traumatic events that can happen to a family. When an infant dies unexpectedly the death is generally attributed to sudden infant death syndrome (SIDS). Part of the devastation of SIDS is that the loss is not only sudden but is unexplained.

Research shows that bedding and items stuffed animals can contribute to crib deaths, but much of the SIDS mystery remains unsolved.

For years now parents have been putting their infants “Back to Sleep” — putting babies to sleep on their backs to avoid the risk of suffocation from pillows, blankets and crib bumpers. But even babies in safe sleep environments die of SIDS, so it's clear that, though research does show that bedding and stuffed animals can contribute to crib deaths, much of the SIDS mystery remains unsolved.

Looking for Brain Abnormalities

One line of SIDS research has focused on a malfunction in the brain that interferes with infants' breathing. Some studies have suggested there is a connection between SIDS and certain problems in the ways in which nerve cells function, particularly how the brain chemical serotonin is used.

A new study looked at circuits in the brainstem, the part of the brain that controls breathing, heart rate, blood pressure and temperature control during sleep. This research details more of the biological links. Problems with brainstem cell function appear to provide some of the answer.

Regardless of whether they had died of asphyxia or not, babies who died suddenly had abnormalities in the function of several neurotransmitters.

Researchers at Boston Children's Hospital looked at the brainstems of infants who died suddenly and were autopsied. They grouped infants according to the circumstances of their deaths — those that had likely suffocated, and those who had most likely not suffocated — based on investigations at the time of their deaths.

In babies who had died of SIDS, whether they had died of asphyxia or not, there were abnormalities in the function of serotonin, serotonin receptors, GABA receptors, and a protein that regulates serotonin. This suggests safe or unsafe sleep environments didn't make a difference. There was something already going on in the babies' brains to make them more vulnerable to SIDS.

“Even the infants dying in unsafe sleep environments had an underlying brainstem abnormality that likely made them vulnerable to sudden death if there was any degree of asphyxia,” study author Hannah Kinney said in a press release. “The abnormality prevents the brainstem from responding to the asphyxial challenge and waking." In other words, brain stem abnormalities make the brain unable to respond normally to a lack of oxygen by waking up or shifting position.

New Strategies for Minimizing the Risk of Sudden Infant Death

The new study is promising in that it helps us understand a little more about the causes of SIDS. Knowing that certain babies may be vulnerable to sudden death because of how their brainstems function could pave the way for better screening and prevention. For example, it could be possible to screen for and treat abnormalities in the baby’s brainstem early on, in order to reduce the risk of SIDS happening in the future.

“Certainly, there are unsafe sleeping environments that can cause any baby to die, such as entrapment in the crib, but if it's just sleeping face down, the baby who dies may have an underlying brainstem vulnerability,” added Kinney. “We have to find ways to test for this underlying vulnerability in living babies and then to treat it. Our team is focused now upon developing such a test and treatment.”

For Parents
Parents should practice safe sleep techniques to reduce the possibility of SIDS. Studies have shown that infants who die unexpectedly are often found sleeping face down with their face in the pillow, or sleeping next to an adult in the bed. The National Institutes of Health reviews the best safe sleep practices for babies on their website. Among the tips they offer:

  • Always place infants on their backs to sleep, for naps and at night.
  • Use a firm sleep surface, covered by a fitted sheet.
  • Your baby should not sleep in an adult bed, on a couch, or on a chair alone, with you, or with anyone else.
  • Keep soft objects, toys, and loose bedding out of your baby’s sleep area to reduce the risk of SIDS and other sleep-related causes of infant death.

The study is published in Pediatrics.