Breastmilk is usually still nutritious after a year, and still has a good complementary effect on the growth and development of the baby. Breast milk at different stages of nutrient content is different, 4~5 days after delivery within the milk for colostrum, the highest nutritional value; 5~14 days for the transition milk; 14 days after the mature milk, milk protein gradually decreased, while fat gradually increased. After a year of breastmilk and colostrum compared to a slight decline in nutrition, but still contains fat, vitamins, etc., can promote the growth and development of the baby. In addition, usually when the baby is 6 months old, complementary foods should be added to provide sufficient nutrition for the baby and promote growth and development. If a breastfed baby lags behind in growth and development, it is recommended that he or she seek medical attention in a timely manner. Under the guidance of a doctor, relevant examinations should be completed to clarify the cause of the disease and provide symptomatic treatment.