Sudden Infant Death Syndrome, or SIDS, is the leading cause of death for babies between 1 month and 1 year old in the United States. Many of these deaths are never explained, and may be linked to underlying medical conditions. But in plenty more cases, newborns die from sleeping in unsafe places.

New recommendations from the American Academy of Pediatrics, along with a new study published in the journal Pediatrics, underscore the dangers of certain sleep environments for babies under 1 year old—especially sofas and comfy chairs, which pose an “extraordinarily high risk of infant death,” according to the new guidelines.

The recommendations for the safest place to sleep remain the same: A baby should be put to sleep on his or her back in a crib or bassinet without any blankets, pillows, crib bumpers, or toys. No monitors should be in the crib, either—no, not even the ones that are marketed as breathing and movement trackers. Such devices, pediatricians warn, give parents a false sense of security about baby’s well-being and aren’t actually proven to prevent SIDS. Baby’s mattress should be firm, and the sheet should be tightly fitted.