What the public health nurse said is correct, all newborn babies need vitamin K; otherwise, there is a risk of significant, and sometimes life-threatening bleeding in the first few weeks to months after birth.

Vitamins are essential chemicals that our body needs. Vitamin D is well known as the sunshine vitamin, we need it for calcium absorption and bone health (and likely much more).

Vitamin K was first discovered by a Danish scientist in 1930s, when he was studying cholesterol metabolism in chicken (talk about coincidence). He noticed that some chicken fed on certain diet had bleeding problems. Further research showed that a chemical isolated from certain food can prevent this bleeding. He called this substance vitamin K. K stands for Koagulation, the Scandinavian spelling for coagulation, which mean blood clot.

Vitamin K is found in large amounts in green leafy vegetables, as well as fruits like bananas, avocados, and kiwis. We get vitamin K from eating these foods. In addition, some bacteria in our large intestines can produce vitamin K, although it is unclear how much of this bacteria-derived vitamin K can be absorbed.

Vitamin K is essential for several proteins involved in the formation of blood clot. When you get a cut and start to bleed, it immediately activates your body’s clotting mechanism to form a blood clot at the injured site, and stops the bleeding within a short time. This process involves many proteins, several of them require vitamin K to become activated.

If we don’t have enough vitamin K, our body cannot form blood clots. Minor injuries can lead to prolonged bleeding. If this occurs inside the head, or in the brain, it can cause brain injury or death. However, vitamin K doesn’t cause stroke, it won’t create blood clot without previous injury.

Pregnant women pass on all kinds of nutrients through the placenta and umbilical cord to their foetus, but not vitamin K. Newborn babies have very little vitamin K after birth. Breastmilk also doesn’t contain vitamin K. Therefore, breastfed babies are deficient in vitamin K until they eat solid food. As a result, babies can develop bleeding problems within days to months after birth, sometimes with devastating consequences.

Babies who are fed with infant formula are also at risk. Although infant formula contains adequate amount of vitamin K for older infants, newborn babies consume much less formula in the first few days to weeks after birth, and can develop vitamin K deficiency bleeding (VKDB) early in life.

As a result, babies in Canada and United States have been given vitamin K injections shortly after birth in the last few decades. This has essentially eliminated VKDB in North America. Because the injection is given into the muscle, vitamin K is absorbed slowly, and provides protection for several months, until they are old enough to eat vitamin K containing food.

There was one report in 1992 suggesting a link between vitamin K injection and childhood cancer. Multiple large scale research in several countries showed that there was no such relationship. Cancer does happen infrequently in children, but it is not due to vitamin K injection.

Any needle injection or blood test will cause pain to newborn babies. There are ways to minimize this pain. You can breastfeed your baby when the nurse is giving her the vitamin K injection. Research has shown that this will reduce her pain perception.

You should enjoy the pregnancy, and trust that nurses and physicians will provide the best care for you and your baby.