9 months baby sleeping on his back generally do not need to be corrected, but need to be observed diligently, if it affects the respiratory function should be corrected in a timely manner. 9 months baby sleeping on his back can make the baby increase the sense of security, not easy to be woken up, the baby’s brain and body development has certain benefits. In addition, sleeping on the stomach can lay the foundation for crawling, can make the baby crawling more sensitive. And babies generally do not sleep on their stomachs all night, will adjust their own posture, so usually do not have to specially correct. However, it should be noted that the baby sleeps on his stomach when parents can be on the side of the guard, diligent observation. Do not let the baby lying on the fluffy quilt and pillow, otherwise it is easy to make the baby sleep with his head buried in the pillow, thus the situation of poor breathing, which may lead to suffocation in serious cases. Therefore, the baby sleeps on his back with breathing difficulties, shortness of breath, cyanosis and other symptoms, first of all, should correct the sleeping position, if the symptoms are not relieved or aggravated trend should take the baby to the hospital for examination in a timely manner.