Yes, the amount of motion is perfectly safe on all levels.
Your baby’s life inside the womb is one of almost constant motion. During the day, imagine the fast jiggling a baby experiences when a pregnant mom hustles to a meeting or takes a hike or goes up and down the stairs…or is in an exercise class! And, a pregnant mom’s breathing rocks the baby in the womb, all night long.
That’s why swinging is one of the most important cues of 5 S’s and is so useful for soothing upsets. But, unlike gentle slow rocking, which is great for keeping a baby asleep – babies require jiggly motion to turn on the calming reflex when they are crying. That’s why some books recommend bouncing on an exercise ball or going for a car ride on a bumpy road. (It is also why adults fall asleep in trains, subways and on bumpy bus rides.)
In The Happiest Baby on the Block, I describe the motion to soothe crying as the “Jell-O head jiggle” because babies need a very fine, fast jiggle to calm. That motion actually activates the balance center of the brain where the reflex gets turned on.
The SNOO platform only moves ½ an inch - back and forth – which is enough to soothe most babies, imitating what it was like in mom’s belly. That amount of motion is perfectly safe and very different form baby “shaking.” Shaking is a dangerous motion where the baby is held by the shoulders and then roughly shaken with the head and neck unsupported, so that the head flails back and forth, like a rag doll. That amount of rough movement causes the brain to be slammed against the inside of the skull at high speed, as well as bruising and internal bleeding.