If you’ve been shopping in the baby section of any store, you’ve probably seen infant head-shaping pillows. You know the ones—those tiny donut-like pillows with an indent or hole in the middle that cradles the back of your baby’s head as they sleep. These infant pillows come in a million colors and patterns and they’re commonly found in all baby sections of major retailers. But according to an FDA warning, they’re not safe.

The U.S. Food and Drug Administration (FDA) just issued a scary warning to parents: Stop using these pillows. Not only are they not approved for any “head shaping” purposes, but they can actually create a dangerous sleeping environment for your little one, contributing to the risk that your baby could suffocate and even die while sleeping on one of these pillows.

“These medical devices are marketed with claims to improve an infant’s head shape and symmetry and claim to prevent or treat flat head syndrome or other medical conditions,” the FDA warning reads. “However, the safety and effectiveness of the use of these medical devices has not been demonstrated.”

“Infant head shaping pillows are not FDA-approved,” the warning continues. “The safety and effectiveness of these products have not been established for the prevention or treatment of flat head syndrome (also known as positional plagiocephaly or deformational plagiocephaly), or the more serious condition where the developing infant’s skull bones join together too early (known as craniosynostosis).”

Related: FDA urges parents to stop using baby neck floats after one death and injury reported

The FDA says it began investigating after receiving reports that these pillows were being marketed as a treatment for flat head syndrome. It notes that head-shaping pillows are not medical devices, and should not be marketed or used as such.

The warning says parents should immediately stop using these pillows due to the risk that they may contribute to sudden unexpected infant death (SUID), including sudden infant death syndrome (SIDS). They also note that if you own an infant head-shaping pillow, you should throw it away—don’t donate or gift it to another family that might then put their baby at risk.

If your baby has been injured by one of these pillows, the FDA asks that you submit a report. This helps the agency collect information about dangerous products and devices and issue more warnings like this one that can protect more vulnerable people.

Related: FDA issues firm warning against the use of infant sleep positioners

They also say that if your infant has a flat or unusual head shape, note that this is common in newborns, is not painful, and in most cases, will resolve on its own. Know that the use of infant head-shaping pillows could actually delay the necessary evaluation and management of harmless conditions, such as flat head syndrome, or more serious conditions, such as craniosynostosis.

Don’t use pillows to try to shape your baby’s head—instead, talk to their healthcare provider about whether you need to take any extra steps. Odds are that you don’t, and your baby will have a nice, round head in no time.