Study shows SIDS may be caused by impaired brain receptors

by Jacob Fuller

Lauren Dempsey, MS in Biomedicine and Law, RN, FISM News 

New research suggests that sudden infant death syndrome (SIDS) may be caused by an abnormality in the medulla oblongata.

This section of the brain makes up the lower part of the brain stem and connects to the spinal cord. The medulla is primarily responsible for essential functions such as breathing, blood pressure, and heart rate.

Researchers from Boston Children’s Hospital and Harvard Medical School conducted the study on SIDS and published their findings last week in the Journal of Neuropathology & Experimental. Details show impaired receptors in the medulla oblongata could be an underlying factor for SIDS.

Dr. Robin Haynes, who led the study, explained that “This 2A receptor is very important in arousing them as a defense mechanism.” Haynes told Fox News Digital that when a baby isn’t getting enough oxygen, the serotonin receptor 2A/C triggers the baby’s natural instinct to gasp for air. However, when there is an abnormality in the receptor it prevents the brain from performing this basic function, and does not signal the infant to “reoxygenate the brain.”


The researchers evaluated brain tissue from 70 infants who died, 58 of which had an altered serotonin receptor 2A/C. The study results suggest that serotonin could be critical in understanding the many factors that may contribute to SIDS, since the neurotransmitter is important in bodily functions by carrying messages from nerve cells in the brain to the rest of the body.

However, Haynes explains that there is “no way to identify an infant at risk for SIDS,” because this abnormality is “undetectable in a living infant.” Experts fall back on safe sleep practices to modify external factors that may contribute to SIDS in an effort to prevent seemingly healthy babies from suddenly dying.


Despite decades of research and safe sleep guidelines that are recommended by the American Academy of Pediatrics (AAP) and the federal government, SIDS is still the leading cause of death in infants and numbers have remained stagnant.

According to the Centers for Disease Control and Prevention (CDC), about 3,400 infants die from sudden unexplained infant death each year, the majority of which can be attributed to SIDS or unknown causes. Data from the CDC shows that accidental suffocation and strangulation in bed account for 905 deaths, the smallest amount reported.

The guidelines for safe sleep recommend putting babies to sleep on their backs on a firm, flat surface at naptime and bedtime, with no pillows, loose bedding, or other objects that could interfere with breathing. The National Institutes of Health identifies the greatest risk factors for SIDS as stomach sleeping, sleeping an infant on soft surfaces and/or with blankets or bedding, cigarette smoke, and co-sleeping/bed-sharing.

Dr. James McKenna, professor at Notre Dame University and “the world’s leading authority on mother-infant co-sleeping in relationship to breastfeeding and SIDS” has spent decades researching infant sleep. McKenna writes that sleeping close to your infant “represents a form of expected physiological regulation and support.”

Research does show that SIDS may be caused by autonomic dysfunction. Australian researchers published findings in The Lancet, last year, which identified an enzyme called butyrylcholinesterase (BChE), which was lower in infants that had died from SIDS. The researchers analyzed blood samples from hundreds of newborns after birth, including 67 infants that later died from SIDS. The findings showed that BChE was lower in these babies, and may correlate to impaired neural function. However, while the authors conclude that this could be used as a measurable way to predict infants at risk for SIDS, it was a very small study sample and additional research needs to be done.