Vitamin K for newborn babies


What you need to know

Why do newborn babies need vitamin K supplement?

Babies are born with less Vitamin K than adults have. Since Vitamin K is used to make some of the factors that make blood clot, a deficiency can lead to bleeding in some babies. This is known as Vitamin K Deficiency Bleeding or VKBD. We can stop this from happening by giving Vitamin K, which we give to ALL new babies since we can’t tell beforehand who is going to have this problem.

The bleeding can happen early, within the first week, or later on, up to when baby is two months old.

The early bleeding disease often happens in babies whose mothers have been taking medicines for illnesses such as epilepsy or bleeding disorders. In this case the baby will often start to bleed from the mouth, belly button, the bottom or from a circumcision (if, it’s been done).

The late bleeding disease tends to happen to babies with liver disease or those who have a problem with absorbing their food.  It happens more often in breast fed babies, since formula milk has been made with more Vitamin K in it than breast milk has. Roughly, half the babies who get late bleeding disease will have a bleed inside their head, which can make them severely disabled or even die.

How is vitamin K given to a newborn baby?

Vitamin K can be given by injection (usually into the big muscle at the top of the leg); Or it can be given as drops into the mouth. Giving Vitamin K by injection seems to stop both early and late bleeding disease. Giving by mouth stops early bleeding disease but we are not sure that it will stop late bleeding disease.

A few years ago, there was a report that suggested that giving Vitamin K by injection might be linked to babies getting Leukaemia in later life. Other research has been done since, which has led to us thinking that this is not true. The best we can say, is that there is a very small chance that the injection of Vitamin K may lead to an increase in Leukaemia.

We have had to decide how to balance these two facts:

  • That Vitamin K by mouth may not be enough to stop late bleeding disease


  • That giving Vitamin K by injection has a small chance of leading to a slight increase in the risk of childhood Leukaemia.

Improving the physical and emotional health and wellbeing of expectant mothers, infants, children and young people throughout Aneurin Bevan University Health Board Area.

(N.B: The Family and Therapies team at ABUHB is NOT responsible for the content on the webpage links that we refer to in our resource sections and linked information to external sites. All information was accurate and appropriate at the time the webpage was created.)

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