There has been another wave of criticism of vitamin K for newborns. Some people call it an unnecessary intervention and question why we should interfere at all if babies are naturally born with low levels of vitamin K.

But “natural” does not always mean “safe.”

Newborns really do have very limited stores of vitamin K. This is due to normal physiological factors: vitamin K does not cross the placenta efficiently, breast milk contains only small amounts of it, and a newborn’s intestinal microbiota is not yet developed enough to produce significant quantities.

The problem is that vitamin K is essential for normal blood clotting. Its deficiency can lead to vitamin K deficiency bleeding, or VKDB, previously known as haemorrhagic disease of the newborn. Bleeding can occur in different parts of the body, including the brain, and may result in severe injury or death.

The question is often asked: if newborns naturally have low vitamin K levels, why not simply leave it alone?

Because natural does not automatically mean harmless.

The human body has many physiological limitations and vulnerabilities. Being born with low vitamin K stores is one of them. That does not mean the potentially serious consequences of this deficiency are a necessary or acceptable part of normal development.

VKDB can occur at different times. There is an early form, which develops within the first 24 hours after birth; a classic form, which occurs during the first week of life; and a late form, which can develop from around one week up to six months of age.

The late form is particularly dangerous. It may occur unexpectedly, sometimes without obvious warning signs, and can involve intracranial bleeding. When bleeding occurs inside the skull, time matters.

VKDB is rare, but rarity does not make it harmless. Before routine vitamin K prophylaxis, late VKDB occurred in approximately 1 in 14,000 to 25,000 infants. Giving vitamin K at birth dramatically reduces this risk.

And this is the entire point of prevention: not to wait for a rare but potentially catastrophic event to happen.

Vitamin K given after birth is not a vaccine. It does not stimulate the immune system and does not protect against an infection. It is a preventive measure designed to reduce the risk of serious bleeding during a period when newborns naturally have very low vitamin K stores.

One reason misinformation around vitamin K can be particularly dangerous is that late VKDB may occur weeks or months after birth. If a child has received a vaccine or another medical intervention shortly before the bleeding begins, the timing alone may be mistaken for proof of causation.

But something happening after an event does not mean it happened because of that event.

The key point is simple.
Newborns naturally have low levels of vitamin K. That is a physiological fact.
But the consequences of vitamin K deficiency can be severe.

Vitamin K deficiency bleeding is uncommon, but it can cause sudden intracranial haemorrhage, permanent neurological damage, or death. A single preventive dose of vitamin K after birth significantly reduces this risk.

Sometimes medicine does interfere with natural processes. That is because nature does not guarantee safety.