Life as a newborn isn't easy. On top of being exposed to a whole new environment, they're tested, prodded, and poked. One of those pokes is a vitamin K shot, a routine part of care for newborns.
What to Know About the Vitamin K Shot for Newborns
Because babies are born with very low vitamin K levels, they’re given a supplement soon after birth. If not, your newborn may develop a condition called vitamin K deficiency bleeding (VKDB) which can cause sudden, dangerous bleeding and even death in the first six months of life.
“The vitamin K shot is a safe and effective way to prevent this form of life-threatening bleeding,” says Rose St. Fleur, MD, medical director of the Center for Breastfeeding at Hackensack Meridian Jersey Shore University Medical Center & K. Hovnanian Children’s Hospital in Neptune, New Jersey. “It’s not a vaccine, but actually a treatment for low vitamin K.”
But in recent years, more parents are saying no to the vitamin K shot. One study found that the number of newborns in the U.S. who didn’t get a vitamin K shot rose from 2.92% in 2017 to 5.18% in 2024.
“Many of the concerns I hear come from parents’ desire to avoid injections, worries about ingredients, or questions about safety,” St. Fleur says.
Here are the facts about the vitamin K shot and how this single injection can protect your child’s health.
What Is Vitamin K?
Vitamin K is one of many vitamins that your body needs to stay healthy. It’s a fat-soluble vitamin. Your body stores extra vitamin K in your liver and other tissues in your body, including your brain, heart, pancreas, and bones.
Unlike some other vitamins, your body can make vitamin K on its own. Another way to get it is by eating certain foods like leafy greens, broccoli, cauliflower, and Brussels sprouts.
What Is Vitamin K Good For?
Vitamin K is often called “the clotting vitamin.” Your liver needs it to make special proteins that help your blood clot. That prevents you from bleeding out when you get hurt.
Vitamin K also helps keep your bones healthy.
Do Newborns Need Vitamin K?
Everyone needs vitamin K to stay healthy. But newborn babies don’t have the same store of vitamin K that older kids and adults have. Vitamin K is one of the few nutrients that can’t easily pass through the placenta, and infants don’t yet have the “good” gut bacteria to make their own vitamin K. Breastfeeding and baby formulas also don’t contain enough of it.
“In the absence of enough vitamin K in their body, babies are unable to form a clot to stop bleeding,” says Mohammad Adnan, MD, medical director of the Tiny Baby Program at Miller Children’s & Women’s Hospital in Long Beach, California. “One in five babies may die if they develop severe bleeding related to vitamin K deficiency.”
VKDB can happen both outside and inside the body, meaning that your baby could bleed internally and you wouldn’t be able to see it.
About half of babies with VKDB bleed inside their brains.
Benefits of Vitamin K Shot at Birth
A vitamin K shot soon after birth can prevent three types of VKDB:
Early-onset vitamin K deficiency bleeding
This starts within 24 hours after birth. It’s linked to certain medications, like anti-seizure medicines, taken by the birth-giving parent, that can interfere with vitamin K.
Classical vitamin K deficiency bleeding
A baby with this kind of VKDB starts to have symptoms two days to one week after birth.
Late-onset vitamin K deficiency bleeding
This type can happen from one week after birth to six months later. It’s most often seen in babies who are exclusively breastfed but didn’t get a vitamin K shot. Newborns who don’t get their vitamin K shot at birth are 81 times more likely to get late-onset vitamin K deficiency bleeding than babies who do get the shot.
After six months of age, your baby can start making and storing vitamin K on their own.
How common is VKDB?
About 1 in 60 to 1 in 250 newborns in the U.S. have early and classical vitamin K deficiency. Late-onset vitamin K deficiency affects 1 in 14,000 to 1 in 25,000 babies.
But if you’ve never heard of VKDB before, you’re not alone. “Many people are unaware of it because routine vitamin K administration is standard practice for newborns,” Adnan says.
Vitamin K Deficiency Symptoms
Most of the time, there are no warning signs before uncontrolled bleeding begins. But you could notice:
- Your baby bruises easily, especially around their head and face
- Nosebleeds
- Bleeding from the umbilical cord or circumcision site
- Skin color that’s paler than usual
- Pale gums in babies with darker skin
- Yellowed eyes in babies older than 3 weeks
- Black, tarry stool
- Bloody stool or urine
- Fussiness (your baby is difficult to soothe for no clear reason)
- Sleeping more than usual or hard to wake up
- Seizures
- Vomiting (not just spitting up)
How is VKDB diagnosed and treated?
If your doctor suspects that your baby has VKDB, they can draw a sample of their blood and check to see how it clots.
VKDB treatment includes:
- Vitamin K injections
- Blood and plasma transfusions
- Surgery
Should Your Baby Get a Vitamin K Shot?
Since 1961, the American Academy of Pediatrics has recommended that all babies get the vitamin K shot. Time and time again, it’s been shown to help prevent vitamin K deficiency syndrome and brain bleeds.
But "with all the information that’s online nowadays, it’s difficult to tell what is true or not, and so much of it can sound scary or confusing, especially when it comes to newborn care,” says St. Fleur. “A lot of what is discussed online is based on outdated information or claims that are not supported by high-quality medical research.”
Here are the facts:
The vitamin K shot is safe.
The most common side effects are redness, swelling, or bruising on the thigh where the shot is given. Only one allergic reaction has been reported to the CDC. Many studies have been done since the early 1990s. None have found a link between the vitamin K shot and childhood cancer.
Vitamin K drops aren’t equal to the vitamin K shot.
“[They’re] less reliable than a single injection and require multiple doses over several months to be effective,” Adnan says. “Additionally, there is no oral vitamin K formulation approved by the FDA specifically for newborns.”
Your baby can’t get enough vitamin K through breast milk.
Eating more vitamin K-rich foods or taking vitamin K supplements still won’t provide enough vitamin K for your baby.
The dose of vitamin K your baby gets isn’t “too high.”
Part of the dose they receive will go into their bloodstream right away and protect them from bleeding issues during their first few days of life. The rest is stored by their body and released slowly as needed.
“Natural” alternatives aren’t effective.
For instance, you might have read that rubbing vernix, the natural substance that covers your baby in the womb, into their skin can provide vitamin K. While vernix does have important antimicrobial properties, “[it] has not been shown to protect babies from bleeding,” St. Fleur says.
You can ask for a preservative-free shot.
“Some versions have small amounts of added preservatives such as benzyl alcohol to prevent bacterial growth,” says St. Fleur. While these have been shown to be safe and are used in many vaccines, many hospitals offer preservative-free versions of vitamin K shots.
You can make the shot less painful.
“Any brief discomfort from the injection can be reduced by holding your baby and breastfeeding during the procedure,” Adnan says.
When parents raise concerns, “I remind [them] of the ‘why’ behind the vitamin K shot,” says St. Fleur. “[It’s] to prevent rare, but very real and potentially lethal bleeding in babies.”
Talk to your doctor so they can help you make the most informed decision for your baby.
