The vitamin K shot given shortly after birth is one of the most important preventive steps in newborn care. It is not a treatment but a precaution: its aim is to prevent bleeding that can occur in the first months and is sometimes life-threatening.

Why are babies born short of vitamin K?

Vitamin K is needed to make the proteins that allow blood to clot. Babies come into the world with low stores of vitamin K because:

  • Very little vitamin K passes from mother to baby across the placenta.
  • The bacteria that produce vitamin K have not yet settled in a newborn's gut.
  • Breast milk contains little vitamin K. Although breast milk is the best food for a baby, it is not enough to protect against this bleeding.

What is vitamin K deficiency bleeding?

In a baby without enough vitamin K, blood cannot clot normally and bleeding can develop. This is called vitamin K deficiency bleeding (formerly haemorrhagic disease of the newborn). The bleeding can appear in the skin, the umbilical cord, the nose or the gut, but it can also occur inside the brain. It has three forms depending on when it appears:

  • Early: within the first 24 hours; mostly in babies whose mothers took certain medicines during pregnancy that affect vitamin K.
  • Classic: between days 2 and 7 of life, as bleeding from the cord, nose or gut.
  • Late: from 2 weeks to 6 months. According to the US Centers for Disease Control and Prevention (CDC), this is the most dangerous form, and 30-60% of cases present with bleeding in the brain. It often starts without warning in babies who seemed perfectly healthy.

According to an estimate cited by the CDC, babies who do not receive a vitamin K shot at birth are 81 times more likely to develop late bleeding than babies who do.

How is it given?

Vitamin K is given as a single injection into the thigh muscle in the first hours after birth. The American Academy of Pediatrics (AAP) has recommended it for all newborns since 1961; in Turkey it is given routinely in the delivery room. The dose is set according to the baby's birth weight. Giving the injection while the baby is skin-to-skin with the mother or breastfeeding can reduce the discomfort.

Some countries also offer oral vitamin K, but it requires repeated doses over several weeks, and protection drops if a dose is missed. A single intramuscular dose provides the most reliable protection.

Common worries

  • "Does it cause cancer?" A link to cancer suggested by a small study in the early 1990s was not confirmed by later, larger studies.
  • "It isn't natural, it's unnecessary." Babies' vitamin K levels are naturally low. The problem is that in some babies this low level turns into serious bleeding, and there is no way to know in advance which baby it will be.
  • "Breast milk is enough." Exclusively breastfed babies who have not received vitamin K are at higher risk of late bleeding.
  • "The shot is very distressing for the baby." It is a brief moment of pain; there may be slight bruising at the injection site.

The risk of refusing: which signs are urgent?

In a baby who has not received vitamin K, especially in the first 6 months, the following signs need urgent assessment:

  • Bleeding from the umbilical cord, nose or a blood-test site that does not stop
  • Unexplained bruises or tiny bleeding spots on the skin (see easy bruising in children)
  • Blood in the stool, vomit or urine; black, tar-like stools
  • Unusual sleepiness, stopping feeding, irritability, repeated vomiting, seizures or a bulging fontanelle

Jaundice lasting longer than two weeks, or pale stools, can point to a problem with the liver or bile ducts, and these babies are also at higher risk of vitamin K deficiency. Prolonged jaundice should always be checked (see neonatal jaundice).

Like the newborn heel prick test and the hepatitis B vaccine given at birth, vitamin K is one of the routine protective steps of the first days. Bringing your birth records to the first newborn follow-up visit helps us see whether anything was missed. You can book an appointment at Özel Düztepe Yaşam Hospital in Şahinbey.