The safest sleeping position for a young baby is on its back. The next safest is on its side. The most dangerous position is on its belly. Most young parents know this. Leading pediatricians advise it. And the practice is linked to a dramatic reduction in the incidence of Sudden Infant Death Syndrome (SIDS). But a popular positioning device intended to prevent rollover can be dangerous in itself, according to leading pediatricians and the U.S. Consumer Products Safety Commission (CPSC).

The commission cites four specific cases of “sleep positioner deaths” of children under 2 in the past eight years. In each case, the child had pressed its nose and mouth against the device and was asphyxiated.

These positioning devices are heavily advertised. A $14.95 “back sleeper with head wedge” is backed by the claim that it “positions baby for sleeping as recommended by American Academy of Pediatrics to help reduce the risk of SIDS.” On the contrary, the academy, in a 2000 report on SIDS, warned against the use of pillows, quilts, comforters, sheepskins, and porous mattresses as significant risk factors. It goes on: “Although various devices have been developed to maintain sleep position or to reduce the risk of rebreathing, such devices are not recommended, because none have been tested sufficiently to show efficacy or safety.”

The trend infant bedding is away from all such devices, including even the bumpers that often line a baby’s bed to prevent the arms or legs or head from getting caught between the side slats. Instead, new cribs must have either closely spaced slats or else solid construction at the baby’s level.

The American SIDS Institute says: “Place infants to sleep in a baby bed with a firm mattress. There should be nothing in the bed but the baby – no covering, no pillow, no bumper pads and no toys. Soft mattresses and heavy covering are associated with the risk for SIDS.” The American Academy of Pediatrics lists similar hazards but also emphasizes prone sleeping, maternal smoking and overheating as risks that can be reduced.

A baby’s death is always tragic, but the tragedy is doubly poignant when the cause turns out to be something intended to protect the infant. Instead of a gadget, the best option is to place baby on his back in an empty crib.