1. Weight and height development indicators The average weight of a four-month-old baby is 5.5-7.5 kg, and the length is 58-67 cm. However, it should be noted that the growth and development of each baby is different, and some babies may be larger or smaller. Therefore, parents should pay attention to their baby\’s growth curve, and if there is a significant deviation from the normal range, they should consult a doctor in time. 2. Development indicators of hand and foot coordination A four-month-old baby can already raise his head and