An infant bed is typically used after it is no longer safe to leave the baby in a bassinet. They have a lower center of gravity, more mass, a broader base of support and can hold a larger baby than a bassinet. Infant beds are more stable than bassinets and as such become desirable when a baby can roll, transferring inertia with their actions; a bassinet may tip, an infant bed won't without concerted effort. Around two or three years of age children are able to defeat their confinement and should be moved to a toddler bed to prevent an injurious fall while escaping their bed (falls account for 66% of emergency room admissions due to infant beds in the United States.).