Administration of Vitamin D to babies

What are the pro and cons for Vitamin D supplementation to all babies?

There are those who are against this sweeping recommendation, saying it should include only babies to mothers who are at risk for low reserve of vitamin D (which is common in populations with little exposure to sunlight, such as the Nordic population, Orthodox religious people, etc.). If a mother who breast feed has low level of vitamin D, than the baby will not get enough vitamin D. in addition, since breast milk is not a sufficient source for vitamin D, and formula has plenty of vitamin D, some say that this recommendation should be given only to breast fed babies (what is better. breastfeeding or formula? Read here).
On the other hand, a strict recommendation to give Vitamin D to all babies will not differentiate formula fed and breast fed babies with normal levels of vitamin D. Thus, under this recommendation, they will also be given a supplement of vitamin D. But since you cannot identify which babies are the ones with normal levels (we will not start drawing blood samples for measuring vitamin D in all newborn babies), and this supplement does not have any side effect, I think it is a reasonable recommendation.

What is the dose of vitamin D, and is there a preference to one brand or another?

The required amount is 400 international units of Vitamin D3 every day. The amount is the same in all babies, including preterm.
There are preparations in which one drop contains the recommended daily amount, and others where the baby will need 2 drops a day (each drop has 200 international units).
– There is no advantage or disadvantage for different brands who are manufacturing vitamin D.
– There are no side effects.
Parents can decide when throughout the day the vitamin will be given. Since routine is important (otherwise you will forget quickly), you should set up a specific hour for the administration each day.
You can administer vitamin D with iron (which mostly is given since the age of 4 months, read here). I recommend parents to give both supplements at the same hour every day, so you will not forget any of them.
There is no need for special blood tests or a doctor order to stop taking vitamin D, you should just stop (as a birthday gift for the baby), at the age of 1.