To make sure their joints develop properly, practice hip-healthy swaddling, endorsed by the American Academy of Pediatrics and the Pediatric Orthopaedic Society of North America: Spread a blanket out flat, with one corner folded down. Lay your baby face-up on the blanket, with their head above the folded corner. Straighten their left arm and wrap the left corner of the blanket over their body, tucking it between their right arm and their right side. Tuck their right arm down, and fold the right corner of the blanket over their body and under their left side. Fold the bottom of the blanket loosely and tuck it under one side of your baby, making sure their hips can move and that the blanket is not too tight.