The normal weight gain pattern for a full-term baby is about twice the weight at birth in the first 3 months after birth, for example, the weight at birth is 3.3kg, and the weight at 3 months of age is about 6.6kg, and the weight of a male baby of the same age will be slightly heavier than that of a female baby of the same age. Usually the average weight of a 3-month-old male baby is around 6.7kg, if it is lower than 5.29kg, it is low weight. Combined with the baby’s length, if the weight is >7.15kg, consider the possibility of overweight. The average weight of a 3-month-old female baby is 6.13kg, if it is lower than 4.9kg, it is low weight, and if it is combined with the baby’s length, if it weighs more than 6.87kg, it is possible to be overweight. If the weight is more than 7.73kg, consider the possibility of obesity. Under normal circumstances, infants should have regular medical checkups after birth for growth level evaluation. 42 days, 3 months, 6 months, 9 months, 1 year, 1.5 years and 2 years after birth are the regular checkup ages. When deviations from normal growth such as length, weight and head circumference are found, early analysis should be requested from the doctor and appropriate intervention should be made.