Because the baby's bones are not fully developed and soft, and they sleep in the same posture for a long time, the weight of the head will exert pressure on the part of the skull that contacts the bed surface, so that this part of the skull gradually sinks, and finally a flat head appears. Therefore, Mabao should adjust the baby's sleeping position in time, and it is best to do it on the back, left, right and prone alternately every 2~3 hours. In particular, long-term supine (easy to cause flat back) and lateral lying (asymmetric development on both sides of the head) should be adjusted in time.