Without vitamin K, your blood can’t clot. That means if you get injured, you might bleed too much and even die.
Most healthy children and adults get the amount of vitamin K they need through their diet and because their gut bacteria produces some, but there’s a notable exception: newborn babies.
Babies are born with very low levels of vitamin K, so in 1961, the American Academy of Pediatrics recommended that all newborns receive an injection of vitamin K in the first hours after birth. We asked UNC Health pediatric nurse practitioner Morgan Fowler about why this injection is so important for newborns.
Why are vitamin K injections recommended for my baby?
Babies are born with very low levels of vitamin K, even if their mothers ate vitamin-rich foods during pregnancy. Vitamin K is found in leafy greens such as spinach and kale, cruciferous vegetables such as broccoli and Brussels sprouts, vegetable oils, soybeans, dairy products and some meats.
“It doesn’t cross the placenta well, but that makes sense,” Fowler says. “You wouldn’t want a clot to form in the umbilical cord because it would cut the baby off from the placenta.”
Babies get their oxygen and all other nutrients from the placenta, but not vitamin K. When your baby is around 6 months old and starts eating solid foods, they will get enough vitamin K through their diet.
“The injection is protective for those first six months, when the baby transitions to solids and their gut is more mature,” Fowler says. “It is most effective when it’s given in the first six hours of life.”
Can my baby get vitamin K through breast milk?
Breast milk has almost all of the nutrients that your baby needs, but vitamin K is a major exception.
“Babies might be able to slowly get some from breast milk or formula, but not enough to be protective,” Fowler says. “It’s just not well-transferred through breast milk.”
What are the risks of vitamin K injections?
Vitamin K injections are very safe for newborns. As with any injection, there may be some pain or swelling where the shot is given.
The vitamin K injection does have a black box warning that an injection could cause anaphylaxis, a life-threatening allergic reaction.
“That warning is intended for elderly patients with heart issues, at a higher dose than what’s given to a newborn,” Fowler says. “There’s only been one documented case of anaphylaxis in a newborn given this injection.”
Researchers have examined whether there’s an association between vitamin K and an increased risk of jaundice or childhood cancer.
There may have been a link with jaundice because of the higher dose given in the 1950s and 1960s, Fowler says, but research has not found an increased risk at the current dose.
In large studies, no links between childhood cancer and vitamin K have been found.
Most hospitals use preservative-free vitamin K injections and vaccines.
What are the risks of not getting a vitamin K injection? Can I just watch for bleeding?
If your baby doesn’t have a vitamin K injection and something causes them to bleed, internally or externally, their blood may not clot and the bleeding may continue. Babies who don’t get the shot have a 1 in 60 to 1 in 250 chance of developing vitamin K deficiency bleeding within their first week of life, and they remain at higher risk for the first six months of life. That means if something causes your baby to bleed, internally or externally, their blood may not clot fast enough.
A baby might have visible bleeding around the umbilical stump or because of an injury. The biggest risk is internal bleeding, particularly in the brain and the digestive system, which you cannot see.
“When there’s bleeding in a baby’s brain, they’re at risk for a fatal stroke or long-term developmental delays,” Fowler says. “Hemorrhages in the brain can be fatal very quickly. One of the early signs of a brain bleed is becoming more lethargic or sleeping more, but new babies sleep a lot—this is something that could easily be missed.”
Similarly, a bleed in the baby’s digestive system will start as fussiness, which is common and might not be recognized until the baby is very sick.
Vitamin K deficiency bleeding has been very rare in the United States because this injection is so effective. In the 1980s, some hospitals in England tried giving vitamin K to only certain newborns and found there was a noticeable increase in dangerous bleeding.
Can vitamin K be given orally?
An injection is the most effective way to get vitamin K into your baby’s system. Oral vitamin K is not approved in the United States, and it’s also not effective because a baby’s gut is so new. The oral vitamin must be administered for weeks to reach the amount that helps your baby’s blood clot, so they still wouldn’t have adequate protection for their first few weeks of life.
Remember that this shot is likely more difficult for you, emotionally, than it is for your baby.
“Some babies don’t even cry for these shots, and most babies are over it in seconds,” Fowler says, noting that parents are invited to be there with their babies, holding them or holding their hand for the injection. “After, you can get right back to skin-to-skin, which calms the baby.”
Does every baby need a vitamin K injection?
Every baby needs a vitamin K injection, no matter how healthy your pregnancy or routine your delivery.
“Some people think this is only for babies who had a traumatic delivery, but all babies need this,” Fowler says.
Delayed cord clamping, or waiting about a minute before cutting the umbilical cord so that a newborn can receive extra iron-rich blood, also doesn’t eliminate the need for a vitamin K injection because vitamin K does not cross the placenta well.
Can I talk to someone about my concerns?
If you’re expecting a baby and have questions or concerns about vitamin K shots, start a conversation with your OB-GYN or your child’s future pediatrician. Many pediatricians offer pre-birth visits to go over any topics of concern.
“If you have a trusted provider, speak with them about this before delivery,” Fowler says. You may also ask doctors and nurses providing your care in the hospital to go over any information you need.
Questions about newborn care? Talk to your doctor or find one near you.