A baby’s sleep grunting may be related to environmental factors, or it may be caused by indigestion, calcium deficiency and other reasons. 1. Environmental factors: If the baby is in an environment where the temperature is too low or too high, resulting in physical discomfort, it may affect sleep, resulting in a lack of sleep, thus showing sleep grunting. 2. indigestion: due to the development of the gastrointestinal system of smaller babies is still immature, coupled with parents feeding improperly, such as a one-time amount of milk or add too much complementary food, easy to lead to indigestion, resulting in abdominal distension, abdominal pain, which may cause sleep grunting. 3. Calcium deficiency: some babies due to poor eating habits, excessive partiality or picky eating, or a large number of snacks, which affects the normal meal, easily lead to the body intake of nutrients is insufficient, is likely to cause calcium deficiency, resulting in nerve excitation, may be manifested in the sleep humming. Baby sleep grunting, may also be related to other factors, accompanied by other obvious discomfort, it is recommended to seek medical advice as soon as possible, by the doctor’s guidance for treatment and adjustment.