The New SIDS Study Everyone’s Talking About Doesn’t Change Anything — Yet

Sudden infant death syndrome, or SIDS, is one of the biggest bogeymen for parents of young children. It’s easy to understand why. According to the Centers for Disease Control and Prevention, about 3,400 infants die from sudden unexpected deaths in the U.S. each year. Unfortunately, experts have been unable to pin down a specific or obvious cause of death, or what puts certain babies at risk of SIDS. Speculation has been that it’s connected with problems in the part of an infant’s brain that controls breathing and waking, but definitive answers have been tough to come by. Yet, if recent media attention is to be believed, a new study changes all of that.

The new study, published in the journal eBioMedicine on May 6 by Australian researchers, has received a lot of attention for potentially unlocking some of the mystery behind SIDS. The researchers measured levels of the enzyme butyrylcholinesterase (BChE) in samples of dried blood spots from 67 newborns who died of SIDS and other unknown causes between 2016 and 2020. They then compared those BChE levels with those from a control group of 655 babies. The researchers found that the children who died of SIDS had significantly lower BChE levels than living children or those who died of other causes.

Because BChE is part of the body’s autonomic system — which regulates blood pressure, breathing, and other involuntary functions — further study into its connection to SIDS is all but guaranteed. However, experts warn that accurate infant risk assessments or changes to current SIDS guidance are far off.

“This new study is interesting, but it is preliminary research with a small sample size. It needs to be repeated on a larger scale and validated in different study formats to see if it holds,” says Christina Johns, M.D., a pediatrician and senior medical advisor at PM Pediatrics.

Other limitations of note include that the findings didn’t measure BChE activity in fresh blood because blood samples were more than two years old. Researchers also included data on children up to 2 years old, even though SIDS deaths are typically classified as those that occur among infants less than a year old. And the researchers used coroners’ diagnoses for cause of death, which rely on less comprehensive examinations than autopsies.

For the foreseeable future, Johns suggests that parents continue to follow standard SIDS prevention guidelines. “I always tell parents that while SIDS is the subject of much research, it is not fully understood yet. So until then, we should continue the ABCs of safe sleep,” she says. “Babies should sleep alone, on their back, and in a crib. These will help avoid a situation such as a tired parent rolling over onto their infant and suffocating them.”

The American Academy of Pediatrics (AAP) notes that “the rate of sleep-related infant death declined significantly in the 1990s after the AAP and others recommended that babies be placed on their backs to sleep, but rates have since plateaued, and SIDS remains the leading cause of postneonatal mortality.” To reduce SIDS risk, the AAP also recommends that cribs have a firm, flat mattress with a fitted sheet, that soft items are kept out of the sleeping space, and that adults in the home avoid smoking.

SIDS remains a complex issue. Although it’s important to be diligent with precautions, parents are also well-served not to let worry over SIDS disrupt life as they patiently wait for the scientific process to build on emerging research.