Federal authorities are urging parents and others who care for infants to stop using all inclined sleepers — even models that have not been recalled — because of the risk of accidental suffocation. Citing findings from a new study, the U.S. Consumer Product Safety Commission (CPSC) says the sleepers have now been linked to more than 70 deaths.

Inclined sleepers are designed to position babies to sleep on an incline of between 10 and 30 degrees.

“The problem is that babies’ necks are very weak and floppy, and their head is heavy. Any time that they are not lying perfectly flat, their head can tip forward and kink off their airway, preventing oxygen flow to their brains,” says Dr. Pilar Bradshaw.

While the CPSC warning is not a recall, several inclined sleepers have been recalled recently. In April, CPSC recalled Fisher-Price’s Rock ‘n Play Sleeper after it said 32 sleep-related infant deaths were linked to the product. The American Academy of Pediatrics has long warned that these products are dangerous.

“Babies should be placed on their backs on a firm, flat surface designed for sleep, such as a crib or bassinet that meets current safety standards. Anything other than that just isn’t safe,” Dr.  Bradshaw says. She reminds parents to keep pillows, blankets and stuffed animals out of a baby’s sleep space.

The CPSC also warns against using infant car seats or bouncers to put babies to sleep. In addition, parents should not rely on commercially sold home apnea monitors that claim to alert you if your baby stops breathing or if the heart rate is unusually slow. The American Academy of Pediatrics says they not reliable.