In the first few months of life, babies typically lack the motor control skills required to
effectively self-soothe through finger sucking. It is fine for babies to have hands unswaddled
while they’re awake, but swaddling the arms down at the sides improves sleep efficacy. With
arms unwrapped, they are prone to startle themselves awake or to get frustrated by being
unable to successfully coordinate bringing the hand to the mouth.
As the baby develops over the first few months, the startle reflex wanes and they begin to
master self-soothing capabilities. At this point, caregivers are encouraged to unsnap the armholes in the SNOO Sleep Sack to allow the baby’s arms to be unswaddled.