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Vitamin K for newborn babies

All newborn babies are offered a vitamin K injection within 6 hours of birth. This is to protect them from a serious bleeding disorder called vitamin K deficiency bleeding (VKDB).

Before your baby is born, your midwife will tell you about vitamin K. They will ask you if it's okay to give it to your baby.

It's your choice whether your baby gets the vitamin K injection or not. But it is strongly recommended. It's a simple way to prevent a very serious disease.


If you decide against vitamin K, you need to observe your baby very carefully.

You'll need to look for symptoms of VKDB, a rare but serious bleeding disorder.

Why your baby needs vitamin K

Vitamin K helps your baby's blood to clot and prevents serious bleeding.

Most babies are born with low levels of vitamin K. They will not produce enough of the vitamin naturally until they are 6 months old. Because of this, they need extra vitamin K.

Risk of vitamin K deficiency bleeding (VKDB)

Vitamin K prevents a rare but serious bleeding disorder called vitamin K deficiency bleeding (VKDB). VKDB can cause brain damage or even death.

Your baby's risk of getting VKDB is 1 in 100 if they do not get vitamin K soon after birth. This risk falls to just 1 in 10,000 if they get vitamin K either by injection.

If your baby gets a circumcision, the risk of bleeding is high if they did not get a vitamin K injection after birth.

How vitamin K is given

Your midwife or nurse will give your baby 1 injection of vitamin K in their thigh within 6 hours of birth.

This is the quickest way for your baby to get vitamin K. It's the best way to prevent them getting VKDB.

Very small or premature babies may need a smaller dose of vitamin K. Your doctor, midwife or nurse will let you know.

If you don't want your baby to have an injection

Your baby can also get vitamin K through their mouth, using a syringe. This is not as good or as effective as an injection. Your baby may spit out the dose or vomit.

If your baby is given vitamin K through their mouth, they'll usually need 3 doses.

First dose

They will get the first dose in the maternity unit or hospital within 6 hours of birth.

Second dose

Your baby will need their second dose when they are between 4 and 7 days old. A healthcare professional needs to give this dose. Ask a pharmacist or public health nurse.

Third dose

If they are breastfed for more than half their feed, they'll need a third dose at 1 month old.

If they are formula-fed, they won't need a third dose because vitamin K is added to formula.

When your baby should not have vitamin K by mouth

Your baby should not get vitamin K by mouth if they:

  • were delivered by forceps, ventouse or caesarean birth
  • were born before 37 weeks
  • are about to have an operation
  • are unwell
  • are on antibiotics
  • find it hard to absorb feeds
  • have diarrhoea

Tell your midwife, nurse or doctor during pregnancy if you have taken any of the following:

  • anticonvulsants - medicines to reduce seizures
  • anticoagulants - medicines to reduce blood clotting
  • medicines for tuberculosis

These can affect the way the body uses vitamin K. Your baby may not be able to absorb vitamin K by mouth.

Safety of vitamin K

Vitamin K has been used for many years in Ireland and around the world. It is routinely given to newborn babies with the consent of parents.

There are no known side effects to your baby. If you have questions about vitamin K, ask your midwife, obstetrician, nurse or GP.

It is important that you have all the information you need to decide what is right for your baby.

Whatever you decide, it is a good idea to write it in your birth plan and to make sure that your birth partner knows your wishes.

Signs of vitamin K deficiency bleeding (VKDB)

Babies with VKDB may start to bleed without a reason from their:

  • nose
  • mouth
  • stomach
  • umbilical stump (belly button)
  • bottom

A tiny number of babies may bleed somewhere else where you can't see, such as in their brain or gut. This can be dangerous and may be life-threatening.

VKDB is rare and usually only occurs between birth and 3 months old. Late VKDB can occur up to 1 year of age.

Be aware of any signs of bleeding if your baby was not given vitamin K after birth.

Emergency action required: Go to your nearest emergency department (ED) if your baby:

  • has unexplained bleeding or bruising
  • is older than 3 weeks and is jaundiced
  • is younger than 3 weeks and their jaundice is getting worse
  • has paler than usual skin (in darker skin you may notice their gums are paler than usual)
  • has blood in their poo, or their poo changes colour to a dark black colour like tar
  • is vomiting blood
  • is drowsy and not waking for feeds
  • is not moving all 4 limbs
  • is very irritable
  • is having any seizures or fits

Tell the doctors and nurses if your baby did not get the vitamin K injection

Treatment for VKDB

Babies who have symptoms of VKDB will need treatment in hospital.

They will be given vitamin K. This is to help and stop any internal bleeding. They may also get blood products if their symptoms are severe. This is to improve their blood clotting ability.

Page last reviewed: 29 March 2023
Next review due: 29 March 2026

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This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 8.