Parents should stop swaddling their babies by three or four months. At this time, most full-term infants are acclimated to life outside of the womb and no longer crave the constriction of a swaddle.
It's also extremely important to give babies over four months old the freedom to move at night. When you stop swaddling baby, you'll be astonished to see how much he travels around his crib during the night. They scooch and flop from one end to the other, several times a night. All that nighttime movement is important exercise. It helps baby enhance his gross motor development, which is crucial for upcoming milestones like crawling, standing and walking. A swaddled baby doesn't have a chance to refine these skills at night.