Vitamin K (for babies)

Babies have low levels of vitamin K in their bodies at birth. Without vitamin K, babies are at risk of getting a rare bleeding disorder. A single vitamin K injection given at birth is the most effective way of preventing this.

Key points

  1. Vitamin K helps blood to clot and prevents serious bleeding.
  2. All babies need vitamin K to produce clotting factors.
  3. Babies have low levels of vitamin K in their bodies at birth.
  4. Without vitamin K, babies are at risk of getting a rare bleeding disorder called VKDB (vitamin K deficiency bleeding) or HDN (haemorrhagic disease of the newborn).
  5. VKDB is serious and can cause brain damage or death.
  6. A single vitamin K injection given at birth is the most effective way of preventing VKDB.

What is vitamin K?

Vitamin K is a substance in our bodies that helps our blood to clot and stops bleeding. Vitamin K is naturally present in the body and is made in the intestine from food.

Why is vitamin K important for my baby?

All babies are born with low levels of vitamin K in their bodies. Vitamin K is made naturally in the intestine but as newborn babies have very little bacteria in their intestine they do not make enough. As your baby grows they will start to make enough vitamin K.

Breast milk contains vitamin K but in too small an amount to provide protection. Too little vitamin K puts your baby at risk of a rare disease called VKDB (vitamin K deficiency bleeding).

What is the risk of my baby developing VKDB?

VKDB is rare and the chance of babies developing it is small, even if they have not been given extra vitamin K. However if babies do develop VKDB, it can cause severe harm, including death or severe brain damage.

  • VKDB is a rare but serious disease (in New Zealand, about 1 in 100,000 babies will develop it).
  • It can cause internal bleeding that can lead to permanent organ, brain damage or death.
  • It is more common in babies who have not been given vitamin K at birth (increasing the risk to about 69 in 100,000).
  • It occurs most often in the first 7 days of life.
  • It can occur up to about 8 months of age in babies with liver or bowel problems.
  • Some babies are more at risk such as those who are born prematurely, are sick or whose mothers are taking certain medications, such as anti-epileptics, anti-coagulants or some medicines for tuberculosis.
  • Giving vitamin K as an injection shortly after birth reduces the chance of getting vitamin K deficiency bleeding to less than 1 in 1,000,000.

Why do babies have low levels of vitamin K?

Babies have low levels of vitamin K in their bodies because:

  • vitamin K is mainly made by bacteria in the gut and there are few bacteria in a baby's gut at birth
  • babies do not get enough vitamin K from their mothers during pregnancy or breastfeeding.

Which babies are most at risk of developing VKDB?

  • all newborn babies have low levels of vitamin K and are therefore at risk
  • premature babies
  • sick babies
  • babies born to mothers taking certain medications, such as some anti-epileptics, anti-coagulants or medicines for tuberculosis
  • babies born by ventouse, forceps or caesarean section.

How is vitamin K given to my baby?

The most reliable way to give babies vitamin K is by one injection into the muscle in the leg (intramuscular injection). One injection given just after birth will protect your baby for many months. It is possible to give babies vitamin K by mouth (orally). However, this is not recommended because:

  • vitamin K is not absorbed as well when given by mouth
  • the protection does not last as long and so 3 doses are required (at birth, at 5 to 7 days and at 6 weeks)
  • there may be doubt as to whether the dose has been swallowed
  • there is a risk that the later dose may be forgotten
  • some babies may have conditions that prevent absorption of vitamin K from the gut.

Can all babies have vitamin K?

All babies need vitamin K. This includes babies who are premature, very small or sick, as well as babies having surgery.

How safe are vitamin K injections?

Research and practice have shown that giving vitamin K by injection at birth is safe and effective. Babies in New Zealand, and in many other countries, have been given vitamin K injections for many years without incident.

Having the injection does not cause any health problems but some babies have a slight swelling or soreness at the site of the injection for a day or two.

One study in the early 1990s suggested that injections of vitamin K might be linked to one type of childhood cancer. Later research has proven that vitamin K is not associated with any kind of childhood cancer, whether it is given by mouth or by injection.

Does my baby have to have vitamin K?

It is your choice whether or not your baby receives vitamin K and whether it is given by injection or by mouth. Giving vitamin K by injection provides the best protection for your baby. Giving vitamin K by mouth (orally) does not provide as much protection for your baby and they will need to have 2 more doses over a period of weeks.

Not giving vitamin K at all means that your baby is at risk of getting a severe, preventable health problem and you should watch closely for any warning signs of bleeding.

When should I seek help?

If you decide against your baby having vitamin K, you need to watch very carefully for symptoms of VKDB (vitamin K deficiency bleeding). You should always see your doctor urgently if your baby has any of the following warning signs:

  • easy bruising increasing
  • bruising around their head and face
  • bleeding from the nose, gut or umbilical cord (bleeding and bruising are not normal in the first months of life)
  • irritability, vomiting, paler than usual in skin or (for dark skinned babies) pale appearing gums which might be due to internal bleeding
  • is over 3 weeks old and there are any signs of worsening jaundice.

Who to ask for more information

Your lead maternity carer (LMC) can give you more information about vitamin K.


  1. Darlow BA, Phillips AA and Dickson NP. New Zealand surveillance of neonatal vitamin K deficiency bleeding (VKDB): 1998-2008. Journal of Paediatrics and Child Health. 18 Feb 2011.​ [Accessed 19/03/2018]
  2. Medsafe NZ. 2013. Information for Health Professionals: Vitamin K prophylaxis in the newborn.
  3. National Health and Medical Research Council, Paediatric Division of the Royal Australasian College of Physicians, Royal Australian and New Zealand College of Obstetrics and Gynaecology, Royal Australian College of General Practitioners, Australian College of Midwives. 2010. Vitamin K for newborn babies: Information for parents. [Accessed 09/10/2018]
Content courtesy of KidsHealth NZ which has been created by a partnership between the Paediatric Society of New Zealand (PSNZ) and the Starship Foundation, supported and funded by the Ministry of Health
Credits: Credits: KidsHealth NZ. Reviewed By: Health Navigator Editorial Team Last reviewed: 04 Jun 2019