What Is SIDS, Exactly? A Pediatrician Explains

It’s a parent’s worst nightmare: Walking over to your baby’s crib and realizing the child is not breathing. SIDS, or Sudden Infant Death Syndrome, is a subgroup of SUID or Sudden Unexpected Infant Death — a category that includes everything from homicide to accidental suffocation to poisoning that results in the death of an otherwise healthy baby. “The specific definition of SIDS is death of an infant under one year that remains unexplained,” says Dr. Michael Goodstein, attending neonatologist and clinical associate professor of pediatrics at Penn State University. The vagueness of the definition is incredibly frustrating for parents, he acknowledges. But while the specific cause of SIDS may never be known, extensive research has been done on ways parents can decrease the risk for their own infant.

“Although we don’t have a full explanation of what happens with SIDS, we do have a hypothesis called the Triple Risk Model, which says SIDS is more likely to occur in certain infants who are vulnerable for some reason, during a critical development period, and when outside stressors are present,” says Dr. Goodstein. What exactly does that mean for your baby? Here, we break it down.

SIDS: Vulnerability

An example of a baby’s vulnerability might be an anatomical abnormality that interferes with serotonin uptake in the brain, says Dr. Goodstein. Serotonin plays an important role in a variety of functions, including maintaining blood pressure, respiratory control, and upper airway reflexes. Unfortunately, there is no test for this condition, and some infants appear to be born with this abnormality.

SIDS: Critical Periods

Babies between the window of one and four months are at greatest risk for SIDS, according to the American Academy of Pediatrics. There may be something about this period of tremendous developmental change and growth that raises the risk, says Dr. Goodstein. Other factors that statistically increase the odds: Being born prematurely, having a low birthweight; having a mother who smoked during pregnancy; and having a younger mother. SIDS is also two to three times more likely in the African American, Native Alaskan and Native American population.

SIDS: Outside Stressors

While the first two factors are mostly not within a parent’s control, environmental stressors are one place where your decisions can play an important role in reducing the odds of SIDS. “These are things like, what position do you put your baby down to sleep in? Is the room overheated? Is the room smoke-free?” says Dr. Goodstein. (Answers: Always on his or her back, keep temperatures moderate, and never smoke near your infant.) “Putting a baby to sleep on his tummy doubles the risk of SIDS,” he adds. “Back sleeping is a very simple way to greatly lower the chances.” You should also use a firm mattress in the crib, and remove any loose bedding that an infant could become entangled with.

What SIDS Is Not

Because of the mysterious nature of the syndrome, many false assumptions have been made about the causes. SIDS is not caused by choking, immunizations or child abuse. Also, SIDS is not contagious. About one in 2,000 infants die of SIDS annually. “You can drive yourself crazy worrying about bad things happening to your baby when you put them down to sleep,” Dr. Goodstein says. “I tell new parents that lots of people die in car accidents every year, but we still drive cars. You do things to make it safer for you, but you don’t stop doing it.”