In normal term infants, vitamin AD is taken orally the second week. If the mother does not supplement vitamin AD during pregnancy, the lack of vitamin AD reserves in the baby's body after birth, relatively less outdoor activities after birth, insufficient sunlight, the lack of vitamin D obtained from the skin through ultraviolet radiation, or the baby grows too fast are the main reasons for the lack of vitamin AD in the body. If it is not supplemented in time, it is easy to affect the development of the baby's bones and teeth, and also has an impact on the visual development. Generally, for normal term infants, it is recommended to take it orally two weeks after birth, until the baby is two years old.
