Most new parents understand that babies should be put to sleep on their backs, rather than face down, to prevent the risk of sudden infant death syndrome (SIDS).  Parents have also heard the message that the safest place for a baby to sleep is in a crib or a bassinet, where the sleep surface is firm.  (Dangerous places for infants to sleep include parents’ beds and sofas, where the sleep surface is soft and cushy.)  Even though parents have heard these messages before, a new study in Pediatrics highlights another important risk factor for SIDS relative to the sleep environment which has not received the attention it deserves:

To reduce risk, the AAP recommends that soft objects and loose bedding such as pillows and pillow-like toys, quilts, comforters, and sheepskin not be placed in an infant’s sleeping environment. However, despite such recommendations, the use of bedding over and under the infant for sleep seems to have remained a common practice.


Catherine Saint Louis tells us how common a practice the use of soft bedding is:

Nearly 55 percent of infants nationwide are put to bed with soft blankets or covered by a comforter, even though such bedding raises the chances of suffocation or sudden infant death syndrome, federal researchers reported Monday.

Their study, published in the journal Pediatrics, is the first to estimate how many infants sleep with potentially hazardous quilts, bean bags, blankets or pillows. Despite recommendations to avoid putting anything but a baby in a crib, two-thirds of black and Latino parents still use bedding that is both unnecessary and unsafe, the study also found.


Drs. Rachel Y. Moon and Fern R. Hauck drill down further:

There were several disturbing findings described in the study. Although there have been declines in potentially hazardous bedding use since the 1990s, the rate of decline has been markedly slower since 2000. Approximately 50% of US parents, and two-thirds of black and Latino parents, continue to use thick blankets, cushions, pillows, and other potentially hazardous soft bedding, either under or covering the infant.


It’s understandable if parents think that using thick blankets on top of the mattress and under the baby’s body, or a pillow under the baby’s head, might provide a warmer and more comfortable sleep surface.  After all, we use blankets and pillows on our soft-as-air mattresses ourselves.  Drs. Moon and Hauck warn us that “soft” and “taut” sleep surfaces mean two different things:

In focus groups, we learned that parents often interpret the recommendation of a “firm sleep surface” as a taut surface. They worry that the surface is too hard and thus uncomfortable, so will use cushions and blankets to soften the surface. If they cover the bedding tightly, so that the covering sheet is taut, they believe that they are following the “firm sleep surface” recommendation, while also making it more comfortable. In addition, parents may be incorrectly interpreting the recommendation against using thick blankets or comforters as meaning only over the infant, rather than under as well.


Blankets and comforters should never be used on top of an infant even if, as Linda Carroll explains, it’s not completely clear how unsafe bedding causes SIDS:

No one knows for sure how loose bedding leads to SIDS. But experts suspect that soft bedding may end up on the baby’s face leading to a rebreathing of exhaled air that is high in carbon dioxide, [Dr. Hiren] Muzumdar said. When adults breathe in air that contains a lot of carbon dioxide, their natural response is to breathe faster.

“If that response is not well developed in an infant that could lead to breathing less instead of breathing more,” Muzumdar said. “And it could potentially lead the infant to stop breathing.”


Previous PediaBlog post on unsafe sleep surfaces and SIDS here.