Vitamin K

A certain amount of vitamin K is needed in your body to help the blood clot, when there is an external or internal injury. Compared with adults, babies are born with low levels of vitamin K but the amount is usually enough to stop bleeding. A few babies, though, 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. You may hear it called either haemorrhagic disease of the newborn (HDN), or vitamin K deficiency bleeding (VKDB).

Bleeding can be very serious for the baby, but it is difficult to tell which babies are most at risk. For this reason, UK health experts recommend that all babies are given vitamin K soon after birth. Your baby is likely to be offered an injection of vitamin K. If you prefer that your baby doesn't have an injection, oral doses are also available. A few parents decide not to give their baby vitamin K at all.

Vitamin K reduces risk of illness

VKDB (or HDN) is a rare but very serious disease. It affects about 1 in 10,000 low-risk babies if they are not given vitamin K. Half of all babies who bleed have a haemorrhage into their brain (intracranial bleeding). This often causes brain damage, and very often the baby dies.

How much vitamin K should babies have?

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. It is not known what the levels of normal newborn clotting factors should be. Artificial baby milks have vitamin K added; this means that a baby fed on artificial milk has adult levels of vitamin K. Scientists do not know if excessive amounts of vitamin K can be harmful.

Are some babies at higher risk?

Some babies appear to be at increased risk of VKDB. Most doctors believe that babies at higher risk 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 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 these babies before they bleed. 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.

Babies who are breastfed and babies fed on artificial milks

Vitamin K levels are higher in colostrum (the first milk you produce) than in mature milk. Levels are also higher in ‘hindmilk’, the milk a baby has towards the end of a feed on one breast.

According to past studies, VKDB was more common among breastfed babies. However, in earlier decades, babies were not breastfed till some time after birth, and strict feeding routines were usual; this probably meant that babies got less vitamin K than would be the case with baby-led feeding. Nowadays, babies are usually helped to feed as soon as possible after birth, thereby receiving a maximum amount of colostrum, and mothers are encouraged to breastfeed for as long and as often as their baby wants. This should reduce the risk of VKDB in babies that are breastfed.

Vitamin K for breastfed babies

If breastfed babies have vitamin K by mouth, the Government recommends that they should have three doses: two in the first week, and a third at age one month.

How to decide

The evidence suggests that higher-risk babies benefit from injection of vitamin K rather than being given it orally. Breastfed babies probably benefit from three doses of vitamin K by mouth. The important thing is to make sure the midwives and doctors who care for you and your baby know your wishes as to whether you want your baby to have vitamin K, and if so which way you would prefer.

What to watch out for

If your new baby bleeds, for example if you find blood oozing from the cord stump, or if bleeding continues for some time after the ‘heel prick’ blood test, or if your baby has a nose bleed or unexplained bruising, then talk to your doctor or midwife. These babies need to be checked in case this bleeding is a sign of VKDB. If your baby has jaundice lasting longer than 2–3 weeks, you should talk to your doctor or midwife because this may be a sign of liver problems, which increase the risk of abnormal bleeding.