The weight of a three-month-old baby is generally double the birth weight, normal male infant height is 55.3-69.0cm, weight 4.69-9.37kg, head circumference 36.7-44.6cm. female infant height 54.2-67.5cm, weight 4.40-8.71kg, head circumference 36.0-43.4cm. in addition to normal height and weight, normal development of the baby three months There will be the following performance: 1. Big movements: the baby’s head can turn around and turn 180°, or the baby can sit when the parents hold it. When the child is lying on the bed, the head can be lifted steadily, even the jaw and shoulders can leave the table, and the front half of the body can be supported by two arms. The baby’s eyes are more coordinated, and both eyes can move and focus at the same time. 3. language development: the three-month-old baby has a certain development in language, and will be very happy to tease him and make joyful laughter. 4. social changes: when seeing his mother, his face will show a sweet 5, cognitive changes: three months of the baby’s visual development, began to have a color toy can quickly respond to the other colors are slow to respond. In the auditory development is faster, there is a certain ability to distinguish the direction, after hearing the sound of the head can follow the sound of rotation 180 °. In addition, the three-month-old baby is recommended to adhere to breastfeeding, the mother should pay attention to eat more fish, lean meat, egg soup and other foods that promote the secretion of milk, which will help the baby sufficient nutritional intake and promote its growth and development.