I still put my 2-year-old to sleep on his back even though each morning he's snuggled on his tummy, head shoved into a corner of his crib. The "back to sleep" message has become ingrained in my new-parent psyche, as the campaign to reduce Sudden Infant Death Syndrome was designed to do when it began 20 years ago after studies showed that placing babies to sleep on their stomachs tripled their SIDS risk.
SIDS, in which an infant dies during sleep from an undetermined cause, can be a huge source of anxiety for new parents - and rightly so. Even after Back to Sleep efforts helped cut the SIDS rate by more than half from 1994 to today, it is still the leading cause of death among U.S. infants aged 1 month to 1 year, with 2,300 cases annually.
The latest research into SIDS is giving parents clearer guidelines for protecting babies during sleep. For example, a recent analysis of more than 1,400 SIDS cases found that having a baby sleep in the parents' bed increases the risk of SIDS by a factor of five for infants younger than 3 months old. Bed sharing presents a risk because, as Children's National Medical Center pediatrician Linda Fu explains to new parents, the airflow around the baby may not be good enough, "and that is all it takes."
In the past decade, researchers identified how low oxygen levels, combined with an underlying brain defect, can cause SIDS. Scientists believe a triple-risk model explains many SIDS cases: A baby has a defect in an area of the brain that controls breathing and arousal; the baby is at an age when those brain areas are still immature; and the baby is exposed to an external stress that compromises his breathing or oxygen levels, or that causes overheating.