Why the Vitamin K shot is a vital part of your newborn's safety net

[5 min read]

In this article: 

• There has been some buzz around the safety of Vitamin K injections for newborns. 
• The goal of the Vitamin K supplement shot is to prevent a potentially devastating bleed before it ever happens. 
• A pair of Providence Swedish experts offer important information about the injection, its safety and why it's a critical part of giving your little one the healthiest start to life.   

After you give birth, there will be lots of activity around you and your baby: checking respiration and encouraging your little one to cry; clamping and cutting the umbilical cord; skin-to-skin contact; and administering preventative medicine like antibiotic eye drops and a Vitamin K injection. This shot helps with blood coagulation and protects babies from a rare but very serious — and sometimes fatal — blood clotting condition during their most vulnerable first months of life. But there’s been some confusing information out there lately about the Vitamin K shot for newborns regarding the injection’s safety and necessity. To learn more, we spoke with two Providence Swedish experts, Elizabeth Meade, M.D., FAAP, IBCLC, NABBLM-C, executive medical director of pediatrics and chief of staff at Swedish First Hill, and Charles S. Hummel, M.D., PhD, FACOG, senior medical director of women's health, who provided some clarity on this critical measure for your newborn’s health.

What is the Vitamin K shot, and why do newborns get it?

Dr. Hummel: Vitamin K is a vitamin our bodies need to help blood clot normally. Without enough vitamin K, bleeding can happen more easily and can be difficult to stop.

Adults usually get vitamin K from food and from bacteria that live in the gut. Newborns are different. Babies are born with naturally low Vitamin K levels because very little crosses the placenta during pregnancy, and their intestines have not yet built up the bacteria that help our bodies make vitamin K. That is why newborns are given Vitamin K shortly after birth: to prevent a rare but very serious condition called Vitamin K Deficiency Bleeding (VKDB), which can cause bleeding in the intestines, around the umbilical cord, and even in the brain. The goal of the Vvitamin K supplement shot is to prevent a potentially devastating bleed before it ever happens.

Dr. Meade: There are three types of VKDB:

• Early: This happens within the first 24 hours. This is usually because the pregnant person may have been taking medications that interfere with vitamin K.
• Classical: We usually see this between 2 days and 1 week after birth. Early and classical VKDB are seen between 1 in 60 and 1 in 250 newborns, usually with no warning signs until the bleeding starts.
• Late-onset: Occurs between 1 week and 6 months after birth. Babies who did not get the vitamin K injection at birth are 81 times more likely to have late-onset VKDB, which is often devastating as these bleeds frequently start in the brain.

Is the Vitamin K shot safe?

Dr. Meade: Yes, the vitamin K shot is safe and effective. Vitamin K, which is a naturally occurring vitamin, is given to the baby in liquid form as an injection and is then stored in the liver and released slowly over several months, bridging the gap until baby is able to start making vitamin K on their own. Over the years, when there has been a concern raised about a potential association of vitamin K with side effects and this has been investigated. For example, one study from the early 1990s explored a possible link between getting vitamin K and leukemia. Many studies involving much bigger groups of children in multiple places were done to look more deeply into this, and none found any association between vitamin K and any form of cancer. Vitamin K is naturally occurring and an important part of our diet, but young infants are at special risk of deficiency because they cannot make enough of their own yet and it does not transfer well through the placenta or breastmilk.

What’s in the shot? 

Dr. Hummel: The main ingredient is phytonadione, which is Vitamin K1.

Because vitamin K is fat-soluble, the medication also needs small amounts of other ingredients to keep it stable and allow it to be given safely as an injection. Depending on the specific product, these may include things like:

• A buffer to keep the pH balanced
• An ingredient that helps the Vitamin K mix properly in liquid
• Many hospitals use preservative-free versions for newborns

If parents have specific concerns about ingredients, they should ask the hospital where their baby is born for more information.

Dr. Meade: One preservative used in many medications and vitamins is called benzyl alcohol. Families may have concerns about this because of reports in the 1980s of very premature infants in neonatal intensive care units who had side effects from benzyl alcohol exposure. It is important to note that benzyl alcohol in high amounts can cause illness but has only been seen in very small or premature infants receiving multiple medications and fluids using that ingredient as a preservative. The tiny amount in a single dose of a medication is not enough to cause illness, even when given in combination with other medications that contain small amounts.

What are the risks of declining the Vitamin K shot?

Dr. Hummel: The main risk is VKDB, especially the late form, which can happen from about 1-2 weeks of age up to 6 months. This bleeding can happen without warning. The most serious type is bleeding in the brain, which can lead to seizures and brain injury. Most late-onset VKDB — about 50% to 75% — happens in the brain, which can be catastrophic.

Babies who do not receive the Vitamin K shot are 81 times more likely to develop late VKDB than babies who do receive it. Vitamin K deficiency bleeding is rare in the United States, but only because most newborns get the vitamin K supplement. In countries where vitamin K is not easily accessible, we see many cases of VKDB.

Can oral Vitamin K be used instead?

Dr. Hummel: Some countries use oral Vitamin K supplements; The challenge is that oral vitamin K is less reliable than the shot.

A few of the many reasons:

• Newborns do not absorb vitamin K through the gut as predictably.
• Oral Vitamin K requires multiple doses over time.
• If a dose is missed, spit up, or not absorbed well, protection is incomplete.
• Oral dosing does not create protect against late-onset VKDB like the injection does

In contrast, the shot gives a dependable supply of vitamin K during the period when babies are most vulnerable.

That reliability and proven benefit is the reason the injection is the standard recommendation in the United States.

Dr. Meade: Other countries have tried oral regimens and gone back to injections. For example, in Denmark in the late 1900s a weekly regimen of oral vitamin K was used. However, because of the increased risk of bleeding with oral vitamin K regimens and because it is difficult to obtain, Denmark went back to injectable vitamin K in 2000 and has used it since then. 

Doesn’t breast milk protect my baby?

Dr. Hummel: Breast milk provides nutrition, immune protection, and many other benefits, but breast milk is naturally low in vitamin K.

Even if a breastfeeding parent eats lots of leafy greens or takes vitamin K supplements, the amount that gets into breast milk is overall not enough to reliably protect a newborn from VKDB.

Dr. Meade: It is one of the only nutrients that breast milk does not reliably provide to babies! 

How do you counsel parents who may be skeptical or unsure about their choice? 

Dr. Hummel: My pediatrics and OB/GYN colleagues understand that some parents are unsure, for a number of reasons: they are trying to make a thoughtful decision. They want to avoid unnecessary interventions. They want to understand what is being given to their child and why. The vitamin K injection is part of a newborn baby's safety net. The risk we are trying to prevent — bleeding in the brain or another serious bleed — is rare, but it is real. The injected form of vitamin K is very effective at preventing it. The main risk of the injection is brief discomfort, possibly some redness around the site. That's about it.

Will it hurt? Can we wait?

Dr. Hummel: Yes, the shot can hurt briefly. The discomfort usually lasts only a few seconds. There are also ways to make it easier, holding baby skin to skin, feeding during or after the shot, using calm sound/voice/touch, or doing alongside other newborn care like baby's first bath. The shot should be given as soon as possible, waiting a few days just adds risk! The goal is to provide protection before there is a problem.

Anything else parents should know?

Dr. Meade: Vitamin K is not a vaccine. It is a vitamin — a nutrient babies are naturally low in when they are born and are unable to get through breast milk. I sometimes describe it as giving the baby a starter supply of something their body needs but has not had time to build up yet. Although there are many difficult decisions to make for your child, getting the vitamin K newborn shot should be an easy "yes."

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About the Author

There's a reason why more babies are born at Swedish every year than any other health system in western Washington - bringing babies into this world is our mission. The Swedish Pregnancy & Childbirth Team is committed to giving you relevant and actionable insights on how to care for yourself and your child as you navigate the trimesters of your pregnancy.

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