700 Children's® – A Blog by Pediatric Experts

Why Does My Baby Need a Vitamin K Shot?

Oct 15, 2019
Infant baby sleeping in mother's arms

One of the first decisions that you'll make as a new parent is whether or not to give your child vitamin K. Vitamin K is a fat-soluble vitamin typically found in leafy greens. This vitamin is essential for clotting factors made by our livers. Without it, we are at risk of bleeding. Unfortunately, our bodies do not make vitamin K - we must eat foods that contain vitamin K to make clotting factors. Another way to get vitamin K is from the healthy bacteria in our gut.

Newborns, however, don't have these options. They cannot eat leafy greens and do not yet have bacteria in their guts. Newborns are at high risk of being vitamin K deficient, or having low stores of vitamin K.  There is poor transfer of vitamin K from mother to fetus through the placenta while in the womb. Additionally, breast milk does not provide enough vitamin K to protect from infants from bleeding. Newborns also have immature livers and are not able to effectively use the small vitamin K that they do have.

Why Is Having Low Vitamin K Bad for Your Baby?

Because newborns are low in vitamin K, they are risk for bleeding. This is called vitamin K deficient bleeding, or VKDB. Bleeding may occur in the GI tract (stomach, intestines, etc), at their circumcision site, or in the head. Head bleeds, or intracranial hemorrhage, is what your pediatrician is most worried about for your newborn. Head bleeds can lead to permanent neurological damage and even death. Some babies are at higher risk than others, such as babies with biliary atresia, cystic fibrosis, or who have mothers on anti-seizure or anti-clotting medicines. However, all babies are at risk of vitamin K deficient bleeding.

When Is My Baby at Risk for Vitamin K Deficient Bleeding?

Babies can have early-onset, classic, or late-onset vitamin K deficient bleeding.  In early VKDB, babies bleed in the first 24 hours of life.  This is most likely to happen in infants whose mothers take medicines that decrease the effectiveness of vitamin K, like anti-seizure medicines. Classic VKDB happens between ages 1 and 4 weeks – it is prevented by infants receiving vitamin K at birth.  Late VKDB can happen as late as 8 months after birth and is highly associated with head bleeds.

What Should I Do to Prevent Vitamin K Deficient Bleeding?

In order to decrease the risk of head bleeds and other types of bleeding, the American Academy of Pediatrics (AAP) recommends giving 0.5 mg to 1 mg of vitamin K via intramuscular shot. Those babies who receive the Vit K shot are 81 times less likely to have vitamin K deficient bleeding.

Many parents have asked me about oral vitamin K as an alternative to the vitamin K shot. Research is ongoing about the effectiveness about oral vitamin K, but there is no oral formulation approved in the US to decrease the risk of VKDB. In countries where oral Vitamin K is more common, they have seen an increase in late Vitamin K Deficient bleeding (at ages 3 weeks to 8 months). This is especially true in solely breastfed babies, as breastmilk does not contain sufficient vitamin K to prevent bleeding.

Are There Risks Associated with the Vitamin K Shot?

In the early 90's, one researcher raised concerns about an association with the vitamin K shot and childhood leukemia. This association has been debunked by numerous high-quality studies; there has been no association found between the vitamin K shot and childhood leukemia. Additionally, many parents worry about the possibility of mercury in the vitamin K shot. The Vitamin K shot does not contain mercury derivatives. You can follow the link below to the ingredient list for the vitamin K shot.

So, Why Does My Child Need Vitamin K?

Our bodies need Vitamin K to stop bleeding. Newborns are deficient in it. Pediatricians are worried about life-threatening bleeding, including bleeding in the head in newborns. The vitamin K shot is the safest and most effective way to prevent vitamin K deficient bleeding in the newborn.

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Featured Expert

Nationwide Children's Hospital Medical Professional
Karen Allen, MD

Karen Allen, MD is a 3rd year pediatric resident at Nationwide Children’s Hospital. She completed her medical school training at The Ohio State University and her undergraduate degree at the University of Notre Dame. She has a special interest in Safe Sleep, fever in the neonate, and other newborn issues. She plans on completing a Hospital Medicine fellowship after completing a chief resident year.

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700 Children’s® features the most current pediatric health care information and research from our pediatric experts – physicians and specialists who have seen it all. Many of them are parents and bring a special understanding to what our patients and families experience. If you have a child – or care for a child – 700 Children’s was created especially for you.