BabyVit D3 Drops (10ml). Vitamin D for babies 0 to 12 months.. Give your baby 5 micrograms of vitamin D3 as a supplement every day from birth to 12 months if they are:. breastfed. taking less than 300mls or 10 fluid oz (ounces) of infant formula a day. All babies who are being breastfed should continue to get a vitamin D supplement after birth, even if you took vitamin D during pregnancy or while breastfeeding.. You do not need to give your baby a vitamin D supplement if they are fed more than 300mls or 10 fluid oz (ounces) of infant formula a day. This is because there has been an increase in the amount of vitamin D added to infant formula.. This is due to a change in EU law as of February 2020.There are many suitable infant vitamin D3 supplements available to buy in Ireland. Use a supplement that contains vitamin D only.. Why babies need vitamin D. Vitamin D helps us to build and maintain strong bones and teeth.Our bodies can make vitamin D from the sun. But babies cannot safely get the vitamin D they need from the sun.Your baby needs vitamin D because:. their skin is very sensitive to the sun and should not be in direct sunlight. their food (breastmilk or solid foods) may not have enough vitamin D in it. between 0 to 12 months babies grow very quickly and have a greater need for vitamin D to form strong bones. Research shows that vitamin D plays an important role in helping the immune system.