Look at this...

If a mother has a low level of vitamin D during pregnancy, the baby should also have a vitamin D supplement for at least 1 year and have some sun exposure. The supplement is a vitamin mixture such as Pentavite.

Breastfed babies
If a mother has low levels of vitamin D, breast milk is not a good source of vitamin D.
It was the breastfed baby bit I was intrigued by. So Vit D cannot be simply transferred by BM. Interesting...