For many parents, the specter of sudden infant death is one of the dominant anxieties in the chaotic early weeks with a newborn. It is a fear that drives 3 a.m. internet searches, and prompts incessant checking to make sure baby is still breathing.
Part of what makes Sudden Infant Death Syndrome, or SIDS, so terrifying, is that it kills newborns who seem otherwise healthy. It does so without warning. And no one really knows how common it is.
Each year, about 3,500 infants in the United States die from Sudden Unexpected Infant Death, or SUID, a broader category that includes SIDS, according to the Centers for Disease Control and Prevention. Most of those deaths remain unexplained. About one-quarter of them are eventually attributed to accidental suffocation or strangulation in sleeping environments.
But scientists have reason to believe that many of the deaths that remain classified as “unexplained” may not be SIDS after all. This isn’t the first time researchers have refined their understanding of this frightening syndrome. In the 1960s, more than 10,000 infant deaths per year were attributed to SIDS in the United States. In the 1970s, researchers theorized that some cases of SIDS, then called “crib death,” were actually caused by botulism poisoning. Other theories have focused on possible breathing disorders, brain abnormalities, and damage to the inner ear. Since the 1990s, caregivers have been instructed to place babies on their backs to sleep. The “Back to Sleep” public health campaign is widely considered one of the most successful such efforts in modern history. It’s credited with cutting SIDS deaths in half, an astonishing decline, in just two decades.