In the choice of vitamin AD and vitamin D3, you can choose according to the baby’s own situation, such as the baby is exclusively breastfed can be under the guidance of the doctor to choose vitamin AD combined. After the birth of the baby whether breastfeeding or artificial feeding, need to timely supplement vitamin D to promote the absorption of calcium. Vitamin D3 is routinely used. its main role is to prevent and treat rickets. Vitamin D supplementation is started within a few days after birth in newborns. Vitamin A is also beneficial to the growth and development of infants, as it is a fat-soluble vitamin. Since vitamin A is mostly added to formula milk, if the baby is purely formula-fed you can simply choose vitamin D3 for supplementation. Breastfed babies need to be supplemented with Vitamin AD under medical supervision. Mixed feeding babies can adjust the dosage according to their own actual situation and discretion. If your baby is exclusively formula fed you can choose Vitamin D3 alone. Mixed feeding babies can adjust the dosage according to their actual situation and discretion. Consult your pediatrician for specific supplementation.