Updated on February 12, 2025.
Sudden infant death syndrome (SIDS) claims the lives of more than 1,300 babies each year, according to the Centers for Disease Control and Prevention (CDC). These unexplained deaths of seemingly healthy children during the first year of life has long been a mystery to doctors and a source of worry for families. But a groundbreaking study has uncovered a possible explanation for SIDS, shedding light on how and why these infants die.
Researchers in Sydney, Australia investigated the theory that that SIDS might be linked to a problem in the part of the brain that controls breathing and arousal from sleep.
For the study, the researchers examined dried blood samples from newborns who died from SIDS and other unexplained causes. They compared these blood samples to blood collected from healthy babies. They found a notable difference in the activity of an enzyme called butyrylcholinesterase (BChE). Among the babies who died of SIDS, levels of this enzyme were much lower than the healthy infants.
Butyrylcholinesterase (BChE) is part of the cholinergic system, which is involved in the regulation of sensory processing, attention, sleep, and arousal. Infants with decreased BChE would not be startled or wake up if they stopped breathing while sleeping.
The study’s findings suggest that decreased BChE is a potential biomarker for SIDS. More research is still needed but it’s possible that newborns could be screened at birth to help prevent SIDS deaths.
It’s not the whole story
Parents are advised by experts from the American Academy of Pediatrics (AAP) to adhere to certain safe sleeping guidelines to prevent SIDS deaths. These include:
- Placing babies on their backs to sleep
- Using firm, flat mattresses
- Removing all soft objects, bedding, pillows, and toys from their sleeping environments
- Not co-sleeping with your baby in bed, but instead sharing a room for at least the first 6 months of life
- Breastfeeding or feeding your baby breast milk
- Using a pacifier during sleep time
- Not smoking in the home
- Not using alcohol, opioids, marijuana, and illicit drugs while pregnant or once you have a baby
- Practicing tummy time during the day
- Getting regular prenatal care while pregnant, and then check-ups with a pediatrician once the baby is born
Though they have risen slightly in recent years, SIDS rates have generally been on a decline for decades, dropping from 130 deaths per 100,000 live births in 1990 to 33 deaths per 100,000 live births in 2019, according to the CDC. But despite this trend, SIDS still accounts for 37 percent of all infant deaths in the United States.
The study’s authors argue that three factors underpin SIDS:
- A vulnerable infant, or a physiological cause
- A critical time in development
- An external stressor, such as sleeping face down or living in a home where people smoke
This study may reveal the missing piece—the specific physical vulnerability that has long eluded doctors, researchers, and families seeking answers.
“This finding represents the possibility for the identification of infants at risk for SIDS infants prior to death and opens new avenues for future research into specific interventions,” the study’s authors wrote. “Further work investigating this area needs to be undertaken with urgency, to determine if specific activity of BChE could potentially be used as a biomarker to identify and prevent future SIDS deaths.”
