The weight of a four-month-old baby is related to gender, feeding and other factors. It is normal for a four-month-old boy to weigh about 5.25 to 10.39 kilograms and for a girl to weigh about 4.93 to 9.66 kilograms. Each baby’s growth and development is different, so the baby’s weight there are individual differences, the general four-month male baby 5.25 ~ 10.39 kg or so, female baby 4.93 ~ 9.66 kg or so is relatively normal, the baby’s body basically will not have a negative impact. If the baby is thin or heavy may affect the normal development of the baby, need to actively seek medical examination and treatment. If the baby is thin, usually need to do a good job of dietary regulation, more to the baby to eat nutritious food, can promote growth and development, generally around 6 months can be complementary feeding, to meet the baby’s body nutrition needs. If the baby is fat, usually need to properly control the diet, it is best not to eat too much at once. Growth and development process, if there are abnormalities, need to consult a doctor in time.