Vitamin K and newborns: what you need to know

Vitamin K: the basics

Your baby will need to have vitamin K after they are born to prevent a rare bleeding disorder called haemorrhagic disease of the newborn (HDN) (Puckett and Offringa, 2000). Vitamin K deficiency can cause HDN so you might also hear people call HDN vitamin K deficiency bleeding (VKDB).

In the UK, you’ll be offered vitamin K as an injection for your baby. If you prefer, they can have it orally instead, although they will need further doses (Puckett and Offringa, 2000; NHS Choices 2016).

It’s recommended that all newborn babies should receive vitamin K at birth (McNinch and Tripp, 1991). If it’s not offered to you, or you’re concerned in any way, ask before you leave hospital or the birthing centre to make sure.

Vitamin K injection

The main advantage of a vitamin K injection given through the intramuscular route in the thigh is that your baby will only need one dose (Puckett and Offringa, 2000). It’s also more effective for preventing HDN. The major disadvantage is that it’s invasive and can cause pain and a small bruise where the injection was given (Puckett and Offringa, 2000).

Oral vitamin K

Oral vitamin K is easy to administer, non-invasive and can be given swiftly and easily by your midwife, with two doses given in the baby’s first week and one given at one month. If they’re formula-fed, it can be given in their bottle. The main disadvantage is that it’s not guaranteed that it will be absorbed when babies are so prone to vomiting at that stage (Puckett and Offringa, 2000).

Haemorrhagic disease of the newborn (HDN)

Babies who get early HDN have it within 24 hours of birth. Classic HDN happens between days one to seven after birth. Late HDN occurs when they are between two and 12 weeks old (Puckett and Offringa, 2000).

• Early HDN happens because of drugs taken by the mum in pregnancy passing through the placenta and inhibiting vitamin K activity.
• Classic HDN happens when babies don’t get enough vitamin K through breast milk.
• Late HDN is linked to babies not absorbing vitamin K because of liver disease or not getting enough vitamin K in their feeds. Late HDN is often linked to high rates of infant deaths caused by internal bleeding.

(Sankar et al, 2016)

What does Vitamin K do?

Vitamin K helps blood to clot. Yet the difficulty is that our bodies can’t store it very well.

In a newborn baby, some vitamin K comes through the placenta but at times this is not enough. That means a small number of newborn babies develop a deficiency (Puckett and Offringa, 2000). Newborn babies receive extra vitamin K to help prevent them getting HDN and life-threatening bleeding in the first hours to months of their life (Puckett and Offringa, 2000).

How would I know if my baby has a vitamin K deficiency?

If your baby has a vitamin K deficiency, they might bruise or bleed for no apparent reason (CDC, 2017). Sadly, most babies with HDN show no warning signs before life-threatening bleeds but they might develop any of the following signs:

1. Bruising that’s particularly around your baby’s head or face.
2. Bleeding from the nose or umbilical cord.
3. Skin colour that’s paler than usual, or pale gums in darker-skinned babies.
4. In babies over three weeks old, the whites of their eyes turn yellow.
5. Blood in the baby’s poo – it might look black, dark or sticky.
6. Your baby vomits blood.
7. If a baby is irritable, excessively sleepy, has seizures or is vomiting a lot, they might have had bleeding in the brain.

(CDC, 2017)

Risk factors for HDN

Breastfed babies are more prone to HDN than formula fed babies. This is because formula is supplemented with more vitamin K than you normally get in breast milk (Booth and Rajabi, 2008). 

Other risk factors include babies who:

• are born before 37 weeks
• are born using forceps, ventouse or caesarean section
• are bruised during birth
• had breathing difficulties at birth
• have liver problems or were poorly at birth
• have mothers who took drugs for epilepsy, to prevent clots or for tuberculosis during pregnancy.

(NICE, 2006)

What if I say no to vitamin K for my baby?

Most parents take up the offer of vitamin K but you don’t have to. In babies who did not receive vitamin K at birth, around 0.25% to 1.7% will develop classic vitamin K deficiency bleeding (Scientific American, 2014). Five to seven per 100,000 babies will develop late VKDB. (Pukett and Offringa, 2000)

This page was last reviewed in April 2018.

Further information

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 0300 330 0700. You might find attending one of NCT's antenatal courses or NCT New Baby groups helpful.

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.