The Vitamin K Shot for Newborns: Questions Answered

Shortly after birth, your baby will likely be offered a vitamin K shot. It is one of the first things a newborn receives, along with eye ointment and a hearing screen, and it often happens while parents are still catching their breath. If you want to understand the shot before your baby arrives, or you have been hearing mixed messages about it, this guide answers the most common questions.

What is vitamin K, and why do newborns need it?

Vitamin K helps blood form clots. Without enough of it, a cut or a bump can keep bleeding, and bleeding can happen inside the body where you cannot see it.

All babies are born with very low levels of vitamin K. Only small amounts cross the placenta before birth. Breast milk is low in vitamin K. And the gut bacteria that make vitamin K in older children and adults take time to grow in a newborn. Babies stay at higher risk until they start eating solid foods, usually around 4 to 6 months.

What is vitamin K deficiency bleeding?

Low vitamin K can lead to a condition called vitamin K deficiency bleeding, or VKDB. It used to be called hemorrhagic disease of the newborn. VKDB can appear:

• Early, in the first day of life. This is rare and usually linked to certain medicines the mother took during pregnancy.
• In the first week, often with bleeding from the cord stump, bruising, or bleeding after circumcision.
• Later, from about 1 week up to 6 months, most often between 2 and 8 weeks. Late VKDB is the most dangerous kind. It often involves bleeding in the brain, and it can cause lasting brain damage or death.

One of the hardest things about VKDB is that there is often no warning. A baby can look completely healthy until a serious bleed happens. Late VKDB happens mostly in breastfed babies who did not receive the vitamin K shot. According to the CDC's facts page on vitamin K deficiency bleeding, babies who do not get the shot at birth are 81 times more likely to develop late VKDB than babies who do.

How does the shot work?

A single shot of vitamin K is given in the thigh muscle soon after birth. The vitamin is stored and released slowly, giving your baby enough to protect them through the months when their own levels are low. The American Academy of Pediatrics has recommended this shot for all newborns since 1961.

You can ask for the shot to be given after you have had skin-to-skin time and a first feeding. The CDC notes that it can be delayed up to 6 hours after birth to allow for early bonding. Holding your baby skin to skin, or breastfeeding during the shot, may help comfort them.

Is the shot safe?

Studies have shown the vitamin K shot is safe for newborns. Side effects are minor, such as brief pain, a little bruising or soreness where the shot was given.

Some parents have heard that the shot is linked to childhood cancer. That concern came from one older study. Many later, larger studies did not find a link, and health groups including the AAP continue to recommend the shot. Others have questions about the ingredients. If that is your concern, ask your birth hospital which product they use and what it contains. Your pediatrician is happy to talk through any of these questions.

What happens if parents decline the shot?

Some families decline the shot, often because they want to avoid needles in the first hours of life or prefer a natural birth experience. If you are thinking about declining, it helps to know:

• Your baby's risk of VKDB, especially the late, serious kind, is much higher without it.
• Your baby's care team and pediatrician will need to know, because it changes how they think about bruising, bleeding or unusual sleepiness in the early months.
• You can change your mind. If you declined at birth, talk to your pediatrician soon about giving it.

What about vitamin K by mouth?

Some parents ask about giving vitamin K drops by mouth instead. The AAP does not consider oral vitamin K an equal substitute for the shot. Oral doses have to be given several times over weeks, are absorbed less reliably, and can be spit up or missed. Studies show they do not protect against late VKDB as well as a single shot. In the United States there is also no oral vitamin K product approved for this use. If you are considering it, talk it through with your pediatrician first.

Does eating more vitamin K during pregnancy or breastfeeding help?

Eating leafy greens is good for you, but it does not raise the vitamin K in breast milk enough to protect your baby. The shot is still needed.

Warning signs of bleeding

Every baby, and especially any baby who did not get the shot, should be checked quickly for:

• Bruising, especially on the head or face, without a clear cause.
• Bleeding from the nose, the cord stump, or a circumcision or needle site that does not stop.
• Blood in the stool, black and tarry stool, or vomiting blood.
• Pale skin, or yellow eyes or skin after about 3 weeks of age.
• Unusual sleepiness, irritability, a bulging soft spot, repeated vomiting or seizures.

You can find more newborn health information on HealthyChildren.org, the AAP's site for parents.

When to call us

Call your A thru Z Pediatrics office if you have questions about the vitamin K shot before or after birth, if your baby did not receive it, or if you notice bruising or bleeding that seems unusual. Call right away if your baby is under 3 months old and has a temperature of 100.4°F or higher.

Call 911 or go to the emergency room if your baby has a seizure, is very hard to wake, has a bulging soft spot, vomits blood, or has bleeding that will not stop. To talk through newborn care before or after delivery, request a visit.