Is it normal for a 1.5 year old baby to sleep on his back?

One and a half year old babies like to sleep on their stomach is also normal, but not a good sleep position.
In the process of growth and development of infants or children, many children like to sleep on their stomachs, sleep on their stomachs, is conducive to increasing the child’s sense of security, relatively more comfortable.
For one and a half years old children appear, sleeping on their stomachs is also a normal state, but this position is not a good sleeping position, may increase the burden on the heart and lungs, and even the risk of suffocation.
It should be noted that the child appears to sleep on his back posture should be adjusted appropriately, change can be lying down as well as the side of the position of the main, try to avoid long-term sleep on his back.