The risk: They prevent young children from falling out of bed, but portable bed rails have caused the deaths of 18 children since 1990, according to the CPSC. Most were children under age 2 who got trapped in a gap between the bed rail and mattress. The CPSC recently revised the standards for the rails' design, so that most new bed rails won't pull away from the mattress and create a dangerous gap.
Safe strategy: Wait until your child is at least 2 and able to climb in and out of bed before using these. Use them only on full-size twin beds with a mattress and box springs, not on toddler beds or bunk beds. (Many toddler and bunk beds come with attached rails, which are safe.) Check every night to make sure that the rails are snug against the mattress.