After 42 days, the baby needs to go to the children’s health department of the hospital for a physical examination, mainly to monitor the baby’s growth and development and determine the baby’s development, mainly for the following items: 1, weight: weight is an important indicator to determine the baby’s physical development and nutritional status. Measure the weight as much as possible to remove the baby’s outer clothing and pants, shoes and hats, etc.. Indoor temperature is low, pay attention not to catch a cold, no undress, the measured data should be subtracted from the weight of clothes and diapers worn by the baby. 2, length: length is a major indicator of the baby’s bone development. Human body length is affected by many factors, such as genetics, endocrine, nutrition, disease and activity exercise, such as early detection of abnormalities to timely treatment. 3, head circumference: head circumference is a response to the baby’s brain development, the size of the brain capacity, but also an important indicator of the baby’s physical development. The baby’s head circumference grows too fast or too slow, are not normal. Whether there is brain dysplasia, hydrocephalus or head malformation, etc. 4, chest circumference: chest circumference is to evaluate the development of the baby’s chest, including the development of the lungs, the development of the thorax and the degree of development of the chest and back muscles and subcutaneous fat. The size of baby’s chest circumference is related to physical exercise and nutrition. 5.Cardiopulmonary auscultation: Cardiopulmonary auscultation is also a basic indicator to understand the baby, if abnormalities are found further examination is needed under the guidance of the doctor. Doctors usually make preliminary judgments based on these physiological monitoring indicators. 42 days if the weight and height growth is too slow, the first consideration is improper feeding, and the feeding method should be corrected in time after discovery.