One of the most popular crib designs is one step closer to being banned in the United States.

A committee of crib manufacturers, retailers and consumer advocates passed a proposal at a March meeting of the standards organization ASTM International that would ban drop-side cribs. That design allows parents to lower one side for easy access to their children, but the movable side can come apart, trapping the child between the mattress and the rail and leading to injuries such as trapped fingers or fatalities by strangulation or suffocation.

Since September 2007, more than 3 million cribs have been recalled for problems with this feature, and at least four children have died. A larger committee at ASTM will vote on the proposal next.

“If you have no moving parts and less hardware, then you don’t have these gaps and you have a safer crib,” says Richard Lichenstein, a pediatrician at the University of Maryland Medical Center. He has treated children whose fingers have gotten pinched between the rails.

Lichenstein recommends that parents inspect their cribs because many of the incidents were caused by worn-out hardware or improper installation (putting the sliding rail on backward is a common error). He recommends cribs with four fixed sides containing a well-fitted mattress and no blankets or stuffed animals.

The drop-side design helps parents who are short or have bad backs. A new design would have a 6-inch “gate” that would fold down on one side, allowing those parents access to their children without straining their backs.

“I’d hate for cribs to get a bad rap,” Lichenstein says. “I still think that’s where kids need to sleep.”