The number of infant deaths linked to crib bumpers has increased in recent years, according to a new study. Crib bumpers are padded blankets that can be placed inside a crib, to prevent a baby’s limbs from getting stuck between the slats. Doctors’ groups recommend against using them, however.

In the new study, researchers found that, over the seven-year period between 2006 and 2012, there were 23 deaths tied to crib bumpers reported to the U.S. Consumer Product Safety Commission (CPSC). This number is nearly three times higher than the average during each of the three previous seven-year spans, when there were eight deaths tied to the use of crib bumpers reported to CPSC.

“Crib bumpers are killing kids,” study author Dr. Bradley T. Thach, a professor emeritus of pediatrics at Washington University School of Medicine in St. Louis, said in a statement. [7 Baby Myths Debunked]

Bumpers are more dangerous than the researchers originally thought, Thach said. “The infant deaths we studied could have been prevented if the cribs were empty” of crib bumpers, he added.

In the new study, the researchers looked at data from the CPSC that showed that, between 1985 and 2012, 48 infants died in incidents involving crib bumpers. During this time, another 146 babies were involved in nondeadly incidents with crib bumpers, in which the babies nearly suffocated or choked, or were nearly strangled.

The researchers also looked at which of the infant deaths were caused by crib bumpers alone, and which were caused by a combination of crib bumpers and other clutter in the cribs. Of the 48 infant deaths examined in the study, 32 were caused by bumpers alone, the study found. For example, in 13 of these cases, the infants became wedged between bumpers and crib mattresses, the researchers found.

The findings suggest that these 32 deaths could have been prevented if crib bumpers had not been used in the cribs, the researchers said.  

The remaining 16 deaths could have been prevented if either the bumpers or other objects had not been present in the cribs, the researchers said. For example, nine of the 16 deaths occurred because the infants were wedged between bumpers and pillows.

Moreover, the researchers looked at other, related data on infant deaths and crib bumpers, which came from the National Center for the Review and Prevention of Child Deaths. These data revealed reports of 32 additional infant deaths related to the use of bumpers that occurred in 37 states between 2008 and 2011. After combining this information with the data from CPSC, the researchers found that the number of fatalities linked to the use of cribs in recent years was 77.

The researchers said they suspect that the number of infant deaths tied to the use of crib bumpers may be even higher, as this issue tends to be underreported. “There may be many more deaths than we are reporting here,” Thach told Live Science.

Despite these data, crib bumpers remain popular among expectingparents who see the products in baby stores, magazines and catalogues, the researchers said.

“When they go into a baby store to buy a crib, they see all cribs lined with bumpers, and that sends a false signal that if they are selling them, they must be safe,” Thach said.

The only solution to the issue of bumper-related infant deaths and injuries would be a nationwide ban on the sale of crib bumpers, the researchers said.

There are currently no federal regulations regarding crib bumpers’ safety, the investigators said. However, the state of Maryland banned the sale of these items in 2013, and Chicago banned their sale in 2011, the researchers said, suggesting that the CPSC should ban the sale of crib bumpers everywhere in the country.