Written by:

Dr Sarah Montgomery-Taylor


Dr Montgomery-Taylor is a paediatrician working in London with particular clinical interests in acute paediatrics. Her wider areas of research include child public health, delivery of integrated care, and digital health.

Vitamin K and the newborn baby

In this article:

  • Immediately after childbirth
  • Vitamin K deficiency bleeding
  • Studies and research
  • Vitamin K replacement
  • Risks of giving vitamin K
  • Feeding options
  • Signs of VKDB
  • Main Points
  • References

Vitamin K and the newborn baby

Immediately after childbirth

When your baby is born, one of the first things that should happen is they will be given a dose of vitamin K in order to protect them against serious bleeding. You will be asked in advance whether you want this for your baby when making your birth plan. Here you can find some more information about why all newborn babies are offered vitamin K, what the options are for how it’s given, and what the risks and benefits of these are.

Vitamin K deficiency bleeding

Some newborn babies can develop a problem called haemorrhagic disease of the newborn (HDN), now more commonly known as vitamin K deficiency bleeding (VKDB) after it was more recently found to have this cause. All babies are born with relatively low levels of vitamin K but in a small proportion of babies (1 in every 10,000 who are born) their very low levels of vitamin K can cause significant bleeding. Vitamin K is needed by all of us as part of the body’s own mechanism to stop bleeding – this is called the clotting pathway. If there is not enough vitamin K, bleeding can easily occur, and if it is inside the body, it can be hard to know that this is happening or stop it. VKDB can be classified by the time in which it occurs and it may present in slightly different ways: early (first 24 hours of life), classical (second to seventh day of life) and late (two to twelve weeks of life). Places that the bleeding can occur include the nose or mouth, the gut, or the brain. If there is bleeding into the brain (this happens in about half of cases), it can cause brain damage or even death.

Studies and research

Since the introduction of vitamin K administration to newborn babies, the number of babies affected by VKDB has drastically dropped and studies have shown it now only really occurs in untreated babies. A major study in the 1940s showed a fivefold reduction in death from bleeding in babies who were given vitamin K at birth*.

There has been some variation in guidance over the years as to whether routine administration is required or just for those at risk. There are some factors that make some babies at higher risk than others for having VKDB. These include prematurity; a difficult delivery (for example, the need for forceps); babies suffering from liver disease, who have feeding issues or poor absorption in the gut, or who are unwell around the time of birth; and babies born to mothers taking certain medication (anticoagulant, anticonvulsants or tuberculosis treatment). Exclusively breastfed babies are also more likely to develop VKDB (see below for more about feeding choices in relation to vitamin K). Most recent systematic reviews (these combine the results of all studies published on a certain topic) demonstrate that in populations where vitamin K is not given, there is a large increase in VKDB, and if it is given there is a significant reduction in VKDB. As some babies with no risk factors at all develop VKDB, the Department of Health currently recommends that all newborn babies receive vitamin K.

Vitamin K replacement

Vitamin K intake for adults comes from various food types including liver and certain vegetables. However, in babies receiving only milk (whether breastfeeding or formula), the amount they receive is insufficient if they are born with very low levels, and the only way for them to receive enough is if they are directly given vitamin K replacement. By replacing vitamin K, the risk of associated bleeding is removed.

There are two ways Vitamin K can be given: either by mouth or by injection into muscle. Both of these give good protection against VKDB but the difference is that an injection is only required once whereas in order for the oral form to be fully effective doses must be repeated. All babies will need two oral doses in the first week and then breastfed babies need a further third dose at one month of age. It is really important that the final dose is not missed in breastfed babies in order to be fully effective.

Risks of giving vitamin K

Vitamin K supplementation is very safe. Studies published in the early 90s raised the possibility of an association between childhood leukaemia and the injected form. Uptake of the injection subsequently dropped off and there was a resultant rise in cases of VKDB. Since then, further studies have been carried out and an expert body has reviewed all the results and concluded that there is no evidence of any association. As with any injection, there is a small risk of localised infection, bruising or bleeding. The risk with oral dosing is that one or more dose will get missed or forgotten and so bleeding may still occur.

Feeding options

As discussed above, breastfed babies need more oral doses in order to receive sufficient vitamin K compared to formula fed babies. This is because formula milk has a small amount of vitamin K added to it and so these babies are receiving some extra in the feed. However, the additional benefit of vitamin K in formula milk should not form the basis of decisions around feeding choice as replacement with either injection or three oral doses is entirely adequate for preventing VKDB in breastfed babies. In general, breastmilk is overall the most complete and beneficial feeding option, although formula milk is a safe and effective alternative.

Signs of VKDB

Should you choose not to give your baby vitamin K, it is really important that you know what signs to look out for should your baby develop VKDB. If you notice blood oozing from the umbilical stump, bleeding for a long time after the heel prick test, or blood coming from their mouth or nose or found in the nappy, it’s important to seek urgent medical advice. Babies who are still jaundiced after two weeks should be reviewed by a doctor as this may indicate a problem with the liver which will make them at higher risk of VKDB.

If you have any further questions, your GP or midwife can give you further advice or support.

Main Points

  • Vitamin K is required to prevent serious bleeding in babies.
  • You’ll be asked whether you want your baby to have a dose of vitamin K at birth when making your birth plan.
  • Babies are given a dose of vitamin K as soon as they are born.
  • Without vitamin K, newborn babies are at risk of developing haemorrhagic disease of the newborn (HDN), also known as Vitamin K deficiency bleeding (VKDB). This is because a small number of babies are born with very low levels of vitamin K.
  • VKDB can present in several different ways: early (occurring in the first 24 hours of life), classical (within the first week), and late (between 2 to 12 weeks of life).
  • VKDB can happen in the nose, mouth, gut, or brain. Bleeding in the brain is extremely serious and can cause brain damage or death.
  • Being given vitamin K at birth greatly reduces the chance of VKDB.
  • Factors such as prematurity and an assisted delivery increase the chances of vitamin K deficiency. The likelihood is also increased if the baby has liver disease or is ill at birth, has poor absorption in the gut, or is born to a mother taking medication such as anticoagulants, anticonvulsants or tuberculosis treatment.
  • Breastfed babies are likelier to have a vitamin K deficiency than bottle-fed babies, but you shouldn’t let this put you off breastfeeding, as there are plenty of other benefits.
  • Some babies with no risk factors at all can still develop VKDB, which is why the Department of Health recommends all newborn babies receive Vitamin K.
  • Vitamin K can be given either by mouth or by injection into the muscle. Oral doses need to be repeated three times, whereas the injection is given just once.
  • Vitamin K supplementation is very safe. If given by injection, there is a small risk of localised infection, bruising, or bleeding.
  • If you notice your baby is bleeding from the umbilical stump, from their mouth or nose, or for a long period after the heel prick test or if you find blood in their nappy, you must seek urgent medical advice.


* Sankar, M. J., Chandrasekaran, A., Kumar, P., Thukral, A., Agarwal, R., & Paul, V. K. (2016). Vitamin K prophylaxis for prevention of vitamin K deficiency bleeding: a systematic review. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/27109090