This article covers:
Why give vitamin K?
Are there any risks?
How much vitamin K should babies have?
Are some babies at higher risk?
Connection between vitamin K and feeding
How can vitamin K be given?
What to watch out for
Your body needs a certain amount of vitamin K to help your blood clot so that you stop bleeding if you have an injury. Compared with adults, babies are born with lower levels of vitamin K but the amount is usually enough to stop bleeding if they have an accident.
A very small number of babies, however, do not have enough vitamin K to prevent internal bleeding problems, if they occur. The risk of bleeding is highest in the first 13 weeks of life. This is either called Haemorrhagic Disease of the Newborn (HDN), or Vitamin K Deficiency Bleeding (VKDB).
VKDB is a rare but very serious disease. It affects about 1 in 10,000 babies if they are not given vitamin K at birth. More than half of all babies who bleed have a haemorrhage into their brain (intracranial bleeding). This is likely to cause brain damage, and often the baby will die.
Bleeding can be very serious for a baby (as described above), but it is difficult to tell which babies are most at risk. For this reason, UK health experts recommend that all babies are offered an injection of vitamin K. If you prefer, oral doses are also available.
Some parents decide not to give their baby vitamin K because they believe the possible risks outweigh the benefit. But what are the risks?
In 1992, a small study found a possible link between vitamin K injections and childhood cancer. This unexpected finding might have been due to chance and therefore needed further study. Since then, larger studies have not found that children had a higher risk of developing childhood cancer after vitamin K injections. It is almost impossible, however, to rule out a link altogether, so it really is a decision for parents to consider what they think is best for their baby.
There is no standard policy across the UK about the dose or the way vitamin K should be given, because there is no strong evidence from which to draw a conclusion. Scientists are unsure about how much vitamin K babies actually need for their blood to clot normally or if very high levels of vitamin K could be harmful.
Some babies appear to be at increased risk of VKDB and doctors believe these include:
- Babies born before 37 weeks of pregnancy.
- Babies whose birth involved the use of forceps, ventouse or caesarean, where bruising might occur.
- Babies who had trouble breathing and did not get enough oxygen when they were born.
- Babies whose mothers are taking anticonvulsants, anti-coagulants, or drugs to treat tuberculosis.
This means that about a third of babies born in the UK would be counted as higher risk. Some studies suggest that many of the babies who develop bleeding have problems with their liver, but it is hard to spot this in babies before they bleed.
Studies have found that VKDB was more common amongst babies who were breastfed than those who were formula-fed. This is because formula milk is supplemented with vitamin K at higher levels than those naturally found in breastmilk.
Vitamin K levels are higher in colostrum (the first breastmilk you produce) than in mature breastmilk. Levels are also higher in ‘hindmilk’, the milk a baby has towards the end of a feed on one breast. In earlier decades, babies were not breastfed as soon after birth, and strict feeding routines were usual; this probably meant that babies got less vitamin K than they do today, when babies are fed when they’re hungry.
Today, babies are also usually helped to feed as soon as they are ready after birth, so that they receive more colostrum, and women are encouraged to breastfeed for as long and as often as their baby wants. This may reduce the risk of VKDB in babies who are breastfed. Read more about feeding here.
If you want your baby to be given a vitamin K supplement you can choose between two methods:
2. Two or three doses of vitamin K by mouth. Two are given during baby’s first week. If you are mainly formula feeding, this is considered sufficient because formula has extra vitamin K added. If you are exclusively breastfeeding, another dose is recommended when baby is a month old.
The evidence suggests that babies who are at higher risk of VKDB benefit from vitamin K by injection, rather than by mouth, because this keeps levels higher for longer, as the vitamin forms a store in the muscle where it was injected. There are risks and downsides to both ways of administering vitamin K though.
The injection may hurt your baby for a short time and this may be upsetting for you but there are rarely any side-effects associated with vitamin K. Very occasionally babies have been given the wrong injection and bruising can occur at the injection site.
With vitamin K by mouth, the main concern is that babies will miss out on the further doses.
You should always consult your GP or midwife if your baby shows any of the following symptoms, as this bleeding may be a sign of VKDB:
- Blood oozing from the cord stump.
- Continued bleeding after the ‘heel prick’ blood test.
- Your baby has a nose bleed or unexplained bruising.
- Jaundice lasting longer than two to three weeks; this may be a sign of liver problems, which increases the risk of abnormal bleeding.
As a parent it is important that the midwives and GP who care for you and your baby understand your wishes about whether you want your baby to have vitamin K and, if so, which method you would prefer.
The injection is given shortly after birth, so it’s a good idea to weigh up the pros and cons and decide before you go into labour what you want to do. This is something you could include in your birth plan and it will be useful for the midwives and doctors who care for you during labour and in the early days.
NCT's helpline offers practical and emotional support in all areas of pregnancy, birth and early parenthood: 0300 330 0700.
Make friends with other parents-to-be and new parents in your local area for support and friendship by seeing what NCT activities are happening nearby.
Health Scotland posts information on vitamin K.
More detailed information is available from MIDIRS (Midwives Information and Resource Service).