Infants make forceful grunting, may be physiological factors, gastrointestinal flatulence, lack of nutrients and other reasons. 1. Physiological factors: infants before the age of one, due to the central nervous system of the brain is not mature enough, the external environment is not very adaptable, in the change of the environment, it is likely to make a strong force, there is a grunting performance, but generally does not affect the normal sleep and development. 2. Gastrointestinal flatulence: It is related to improper feeding, such as eating too much at one time, which may affect gastrointestinal digestion and lead to gastrointestinal flatulence, and the inability to evacuate the bowels will lead to the baby’s exertion and grunting, which will seriously affect normal eating. 3. Lack of nutritional elements: for example, lack of vitamin D, calcium, etc., may cause infants to make a strong effort to make a grunting sound in their sleep. It is recommended to observe the baby for a period of time, if the baby is often like this, it is necessary to consult a doctor in time.