Written by Dr Samuel Heitner
Consultant Paediatrician and Founder of Telebaby
Shortly after birth, parents are usually offered a vitamin K injection for their newborn baby.
For some parents, this raises understandable questions. Why does a healthy newborn need vitamin K? Is it a vaccine? Is the injection safe? What happens if you decide not to give it? And can oral vitamin K be used instead?
As a paediatrician, I am hearing these questions more frequently.
The simple answer is that babies are born with very low levels of vitamin K. Vitamin K is essential for normal blood clotting and giving it shortly after birth protects babies against a rare but potentially very serious condition called vitamin K deficiency bleeding, or VKDB.
Current Australian health guidance recommends vitamin K for all newborn babies, with the injection being the recommended and most effective option.
Why do newborn babies need vitamin K?
Vitamin K is essential for normal blood clotting.
Babies are born with very low levels of vitamin K. Only a small amount passes from mother to baby during pregnancy, breast milk contains relatively little vitamin K, and a newborn baby’s gut bacteria are not yet established enough to produce sufficient amounts.
This means that even a healthy, full-term baby can be at risk of vitamin K deficiency bleeding.
What is vitamin K deficiency bleeding?
Vitamin K deficiency bleeding, or VKDB, occurs when a baby does not have enough vitamin K for their blood to clot properly.
Bleeding can occur anywhere in the body. It may occur from the umbilical area, within the gastrointestinal tract, or following procedures such as circumcision. The most concerning form is bleeding inside the brain.
Serious bleeding can result in brain injury, organ failure or death.
One of the difficulties with VKDB is that a baby may appear completely healthy before significant bleeding develops. This is why waiting to see whether symptoms develop is not a safe alternative to prevention.
How is vitamin K given to newborn babies?
There are two ways vitamin K can be given to a healthy newborn baby:
• a single injection into the thigh shortly after birth
• vitamin K given orally in several doses
The vitamin K injection is the recommended and most effective option. A single dose provides reliable protection without parents needing to remember additional doses.
It is important to understand that vitamin K is not a vaccine. It is a vitamin that the body needs for normal blood clotting.
Can my baby have oral vitamin K instead?
Yes. Oral vitamin K is an alternative for some healthy newborn babies, but it is important to understand that it is not a single dose.
Healthy babies receiving oral vitamin K require three doses:
1. at birth
2. between three and five days of age
3. at four weeks of age
If your baby is mainly formula-fed, the final dose may not be needed.
The injection remains the preferred option because it provides more reliable protection with just one dose. With oral vitamin K, doses can be missed, and vomiting, diarrhoea or certain medical conditions may reduce how reliably it works.
Is the vitamin K injection safe?
Vitamin K has been routinely given to newborn babies for decades and has a well-established safety record.
Like any injection, vitamin K can occasionally cause irritation, swelling, bruising or tenderness at the injection site. Serious allergic reactions are rare.
When weighing these possible side effects against the risk of severe bleeding, including bleeding in the brain, the benefits of the vitamin K injection clearly outweigh the risks.
Does the vitamin K injection cause childhood cancer or leukaemia?
This is a concern that still appears online.
A study in the early 1990s raised a possible link between vitamin K injections and childhood cancer. This prompted further research, and larger subsequent studies did not confirm an association between vitamin K injections and childhood cancer or leukaemia.
Based on the available evidence, there is no evidence that giving a newborn vitamin K injection increases their risk of childhood cancer or leukaemia.
What happens if a baby does not receive vitamin K?
A baby who does not receive vitamin K remains at risk of vitamin K deficiency bleeding during the first six months of life.
Importantly, being born at full term, having a normal delivery, feeding well and appearing completely healthy do not remove this risk.
Some babies are at even greater risk if they have an underlying condition affecting the liver, bile flow or absorption of vitamin K. Giving vitamin K after birth is highly effective at preventing these potentially serious bleeding complications, including internal bleeding such as bleeding in the brain.
Why are more parents questioning vitamin K?
In my clinical work, both in the paediatric Emergency Department and through Telebaby, as well as during my previous work caring for newborn babies on a postnatal ward and in a Special Care Nursery, I have noticed more parents asking whether vitamin K is really necessary and occasionally declining it.
Often, it is not an immediate refusal. Parents may have read something online, seen concerns raised on social media or simply feel uncomfortable with their newborn having an injection so soon after birth.
I also see some parents who are hesitant about vaccines assume that vitamin K is a vaccine, when in fact it is a vitamin given to prevent serious bleeding.
Ideally, parents should receive information about vitamin K during pregnancy so they have time to ask questions and make an informed decision before their baby is born, rather than having to make that decision shortly after delivery.
Parents should feel comfortable asking questions. The important thing is that they receive clear and accurate medical information so they can make an informed decision, rather than one based on misinformation or fear.
My advice to parents
Vitamin K deficiency bleeding is uncommon, but when it occurs the consequences can be devastating.
It is uncommon partly because giving vitamin K to newborn babies has been routine practice for decades.
This is not about frightening parents or dismissing their concerns. It is about understanding why vitamin K is offered and making an informed decision based on the benefits and risks.
For most babies, I strongly recommend the vitamin K injection because it provides the most reliable protection with a single dose.
If you have concerns about vitamin K, I recommend discussing them with your midwife, obstetrician, GP or paediatrician during pregnancy. This gives you time to ask questions, understand the options and make an informed decision before your baby is born.
Frequently Asked Questions About Vitamin K for Newborns
Is vitamin K a vaccine?
No. Vitamin K is not a vaccine. It is a vitamin your baby’s body needs for normal blood clotting.
Does a healthy baby still need vitamin K?
Yes. Healthy, full-term babies are still born with very low levels of vitamin K. A normal pregnancy, uncomplicated delivery and healthy-looking newborn do not remove the risk of vitamin K deficiency bleeding (VKDB).
Does a formula-fed baby still need vitamin K at birth?
Yes. Vitamin K is recommended for all newborn babies, including babies who will be formula fed. Breastfed babies generally have lower vitamin K levels than formula-fed babies because infant formula contains more vitamin K than breast milk.
However, formula alone does not provide enough vitamin K to protect a newborn from vitamin K deficiency bleeding, so vitamin K is still recommended at birth.
If oral vitamin K is chosen, predominantly formula-fed babies may not require the third and final oral dose.
Is oral vitamin K as effective as the injection?
The injection is the preferred option because it provides reliable protection with a single dose. Oral vitamin K is not absorbed as reliably as vitamin K given by injection, requires multiple doses, and its effectiveness depends on every dose being given at the right time. Vomiting or diarrhoea may also reduce how reliably oral vitamin K works.
Oral vitamin K is generally only suitable for healthy, full-term newborn babies. It is not recommended for babies who are premature, unwell, or have certain conditions that may affect vitamin K absorption.
Oral vitamin K is also not recommended when the mother has taken certain medications during pregnancy that can interfere with vitamin K, including some anti-seizure medications. In these situations, the vitamin K injection should be used instead.
What are the warning signs of vitamin K deficiency bleeding?
Signs may include unexplained bruising or bleeding, bleeding from the umbilical area, blood in the stool or vomit, or excessive bleeding following a procedure such as circumcision.
Bleeding inside the brain may cause more serious symptoms such as lethargy, repeated vomiting, a bulging fontanelle, seizures, or a significant change in your baby’s behaviour or alertness.
Any unexplained bleeding, significant bruising or concerning change in a young baby should be assessed immediately.
What is in the vitamin K injection?
The active ingredient is phytomenadione, also known as vitamin K1. This is the form of vitamin K used to help prevent vitamin K deficiency bleeding in newborn babies.
The injection also contains a small number of other ingredients that help keep the vitamin K stable and allow it to be given as an injection. These include glycocholic acid, a bile acid naturally produced by the liver that helps with vitamin K absorption; lecithin, a type of fat found naturally in the body and in many foods, which helps vitamin K mix with water so it can be injected; very small amounts of sodium hydroxide and hydrochloric acid to adjust the acidity of the solution; and sterile water for injection.
If you are concerned about any of the ingredients in the vitamin K preparation being offered to your baby, ask your maternity team to show you the product information.
Can vitamin K cause childhood cancer or leukaemia?
No. A single study in the early 1990s raised a possible link between vitamin K injections and childhood cancer. Since then, the issue has been extensively studied, and larger subsequent studies have not found an association between vitamin K injections and childhood cancer or leukaemia.
The Australian National Health and Medical Research Council has also concluded that there is no association with childhood cancer.
Can I increase my baby’s vitamin K through breastfeeding?
No. Even if a breastfeeding mother increases her own vitamin K intake, only small amounts of vitamin K pass into breast milk. This does not provide enough vitamin K to protect a newborn baby from vitamin K deficiency bleeding.
Breastfeeding is still strongly recommended and provides many important benefits for babies. However, if you are exclusively breastfeeding, the vitamin K injection is strongly recommended to provide reliable protection against VKDB.
What should I do if my baby did not receive vitamin K at birth?
Speak with your baby’s midwife, community child health nurse, GP or paediatrician rather than waiting to see whether symptoms develop. The appropriate advice will depend on your baby’s age, health and whether any oral vitamin K has already been given.
If your baby develops unexplained bleeding or bruising, becomes very lethargic, has repeated vomiting, seizures or otherwise appears seriously unwell, seek urgent medical attention.
About Dr Samuel Heitner
Dr Samuel Heitner is a Sydney paediatrician who works in the Emergency Department at The Children’s Hospital at Westmead and is the founder of Telebaby, an Australia-wide paediatric telehealth service.
He also worked for many years at Sydney Southwest Private Hospital, caring for newborn babies in the postnatal ward and Special Care Nursery.
Dr Heitner has also discussed increasing vitamin K hesitancy among Australian parents with news.com.au.
References and further reading
1. Gold Coast Health, Queensland Government. Vitamin K Injection for Newborns. Updated 3 June 2026.
2. Queensland Health, Clinical Excellence Queensland. Phytomenadione (Vitamin K1), Neonatal Medicine. Effective March 2026.
3. Sydney Children’s Hospitals Network, NSW Government. First 3 Months: Injections Given After Birth.
4. Simatou E, Tsamantioti E, Hallström A, et al. Vitamin K Prophylaxis in Newborns and Bleeding in Infancy. JAMA Pediatrics. Published online July 13, 2026.
5. Zurynski Y, Grover CJ, Jalaludin B, Elliott EJ. Vitamin K deficiency bleeding in Australian infants 1993–2017: an Australian Paediatric Surveillance Unit study. Archives of Disease in Childhood, 2020.
6. Fear NT, Roman E, Ansell P, et al. Vitamin K and childhood cancer: a report from the United Kingdom Childhood Cancer Study. British Journal of Cancer, 2003.
This article provides general information only and does not replace individual medical advice. If you have concerns about vitamin K or your baby’s health, speak with your midwife, GP or paediatrician.