According to the Parents magazine, “Sudden infant death syndrome (SIDS) causes newborn babies to die in their sleep—often without warning. It’s so unpredictable, in fact, that many pathologists and healthcare providers now refer to it as Sudden Unexplained Infant Death Syndrome (SUIDS), according to Steven A. Shapiro, D.O., chair of the Pediatrics Department at Abington–Jefferson Health…
“The causes of SIDS aren’t really understood. ‘Most babies who die of SIDS appear perfectly normal,’ says Rachel Moon, M.D., a pediatrician at Children’s National Medical Center, in Washington, D.C., and a member of the American Acamedy of Pediatrics’s SIDS Task Force.
“But experts believe SIDS victims have an immature arousal center in the brain. Put simply, they can’t wake themselves up when they’re having trouble breathing. Infants who sleep on their stomach are particularly vulnerable to SIDS—possibly because this position increases the likelihood that they will re-inhale oxygen-depleted air.”
https://www.parents.com/baby/health/sids/new-ways-to-reduce-the-risk-of-sids/