Babies suddenly wake up frequently at night, may be due to lack of nutrients, improper feeding, indigestion and other reasons. 1. Lack of nutrients: babies in the body growth and development will appear lack of nutrients (such as vitamin D), resulting in frequent waking up at night, and even crying and restlessness. Nutritional elements in the body should be checked in time. 2. Improper feeding: nighttime changes in ambient temperature too cold or too hot, overfeeding or underfeeding of babies, diapers are not replaced in time, uncomfortable clothes, etc., will lead to restless sleep, frequent night waking. 3. Indigestion: the baby’s stomach and intestines are not yet fully developed, too hungry and too full can cause indigestion, thus waking up at night. The baby suddenly woke up frequently at night, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.