One year old babies often cry in the middle of the night may be due to the lack of vitamin D, baby hunger, disease state caused. 1. Lack of vitamin D: If it is vitamin D deficiency, not only will the baby cry and restlessness, but also accompanied by excessive sweating, occipital baldness, square skull. In this case, more vitamin D supplement, but also to take the baby for appropriate outdoor activities to promote the absorption of calcium. 2. Baby hunger: baby’s stomach is very small, can not hold a lot of breast milk or milk powder at a time, need to feed on demand, so parents need to feed every once in a while in a timely manner, and to give peace of mind. 3. Disease state: the baby often cry may be physically uncomfortable, such as acute upper respiratory tract infection, etc., can only rely on crying to attract the attention of parents, parents should pay close attention to the baby’s habits, changes in urination and defecation, and give the baby help in a timely manner. More than a year old baby often cry in the middle of the night may also have 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.