Newborn Vitamin K Shot: What the New JAMA Pediatrics Study Means for Parents

If you are expecting a baby, you may be asked soon after birth whether you want the vitamin K shot for your newborn. A new analysis in JAMA Pediatrics, published in November 2026, adds a reason this question is in the news: as slightly fewer newborns in the US received the injection, diagnoses of vitamin K deficiency bleeding went up sharply.

The short version is that major health bodies still recommend vitamin K for every newborn. The American Academy of Pediatrics (AAP) recommends a single injection, and the NHS in the UK recommends vitamin K for all babies, with the injection the most effective route. The new study is an association, not a controlled trial, but its direction matches what the guidance is built on.

This guide is general information, not medical advice. Your midwife, obstetrician or paediatrician knows your baby's circumstances, including whether your baby is early or has other risks, and is the right person to talk it through with. If your baby has unusual bleeding or bruising, get care right away.

TL;DR

Question	Short answer
What is the vitamin K shot?	A single injection into the baby's thigh soon after birth that prevents vitamin K deficiency bleeding (VKDB).
What did the new study find?	More than 11 million US infants, 2017 to 2025: shots fell from 97.7 to 95.0 percent, while VKD rose 216 percent and VKDB 347 percent.
Does that prove the shot decline caused it?	No. It is an association in health records, though the authors say other explanations seem unlikely.
What do the AAP and NHS recommend?	AAP: a single injection for every newborn. NHS: vitamin K for every baby, injection preferred, drops as an alternative.
Is there a cancer risk?	No. Large studies since the 1990s found no link, per the AAP and NHS.
When should I seek care?	Bruising on the head or face, or bleeding from the nose, mouth, gums or cord stump: contact a doctor or emergency services now.

What did the new vitamin K study find?

The paper, led by Dr Elizabeth Wolf of Children's Hospital of Richmond at Virginia Commonwealth University with colleagues including Steven Woolf, was published in JAMA Pediatrics (DOI 10.1001/jamapediatrics.2026.5794). The team analysed deidentified electronic health records from a national database covering more than 11 million infants aged 0 to 6 months, born at 35 weeks or later and seen between 2017 and 2025.

According to the reporting on the study, these were the main numbers:

• The share of newborns who received the injection fell from 97.7 percent to 95.0 percent.
• Diagnoses of vitamin K deficiency (VKD) rose by 216 percent, and diagnoses of vitamin K deficiency bleeding (VKDB) rose by 347 percent.
• Only about 40 percent of infants diagnosed with VKD, and about 19 percent of those with VKDB, were recorded as having had the shot.
• Around 7 percent of VKD cases and 2 percent of VKDB cases also had a diagnosis of bleeding inside the skull.

A fall of under three percentage points sounds small, which is why the size of the rise in cases surprised some readers. When most babies are protected, even a small group who are not can lead to a noticeable number of cases, because the condition is rare to begin with. A percentage increase in a rare event can also look larger than the actual number of babies affected, so it helps to keep both ideas in mind.

An earlier study in the same line of work found that the share of newborns not receiving the shot rose from 2.9 percent in 2017 to 5.2 percent in 2024. The AAP says more than 5 percent of newborns did not receive it in 2024, up from 2.9 percent in 2017.

What can this study show, and what can't it?

This is a records-based observational study. It can show that two things moved in opposite directions over the same years. It cannot prove that one caused the other, and the authors say so.

Some honest limits:

• Diagnosis coding. Electronic records rely on how clinicians code a diagnosis, and coding habits can change over time.
• Missing information. Records may not show whether a shot was given elsewhere, such as at a birth centre or a previous hospital.
• US data only. Rates, practices and refusal patterns differ by country.
• No individual risk. The study does not tell you how likely a particular baby is to have a problem.

The authors reason that the other things that raise the chance of VKD stayed the same or declined over the period, which makes a change in the shot the most likely explanation. That is a reasonable argument, but it remains an argument. The more important point is that the study fits with a long-standing, well-understood mechanism, which is the next section.

Why do newborns need vitamin K at all?

Vitamin K helps blood to clot. Babies are born with low levels because little of it crosses the placenta, and breast milk does not supply enough in the early months. Their gut bacteria, which later help make the vitamin, are not yet established.

The AAP explains that without the shot babies are about 81 times more likely to develop VKDB, and about 1 in 5 who develop it die. It describes how part of the injected dose is absorbed right away and the rest is stored in the liver and released slowly, which is why one injection can cover the weeks until a baby can build its own stores. The AAP also notes that babies remain at risk up to 6 months of age.

VKDB comes in forms depending on timing. Early and classic forms show up in the first days to a week, often as bleeding from the umbilical cord stump or bruising. Late VKDB, between about 1 week and 6 months, is the most worrying. According to the reporting on the new study, it carries a 30 to 60 percent risk of bleeding in the brain, which can cause seizures, lasting brain damage or death. Late bleeding can arrive without warning in a baby who looked well.

Part of why this is hard to talk about is that the shot has worked so well. The researchers describe vitamin K as "a victim of its own success": because VKDB became rare, many parents have never seen it and may not realise what declining the injection can mean.

What do the AAP and NHS recommend now?

United States: AAP

The AAP has recommended a single intramuscular vitamin K dose for newborns since 1961, according to the news report on the study, and describes the policy as in place for over 50 years. Your care team handles timing and dosing; you do not need to work out anything yourself.

On oral vitamin K, the AAP says the medicine "can be absorbed inconsistently when administered orally", which is why experts recommend the injection.

United Kingdom: NHS

The NHS recommends that all newborn babies be offered vitamin K, and describes two options. The injection is one dose at birth, given by a midwife or other health professional, and does not need repeating. The oral option is drops in the mouth, with further doses on a schedule set by your maternity service. NHS trust leaflets such as East Kent Hospitals' guide say the injection is the preferred method and a single dose is the most effective, while drops work only if the baby absorbs them. Ask your team whether drops are suitable if your baby is unwell or born early. The NHS pregnancy hub has more on newborn care after birth.

The cancer question

In the 1990s, one study raised a concern about a link between the injection and childhood cancer. The AAP and NHS both state that many large studies since then have found no evidence of such a link. If this worry is what is making you hesitate, ask your team to go through it with you.

What if I'm unsure about the shot?

Wanting to understand what goes into your newborn's body is reasonable, and a question is not a refusal. Many parents hesitate over the needle, a preference for a "natural" approach, or something they read online. A good conversation can cover:

• What VKDB is and how common it is without the shot.
• Whether your baby has any risks, such as being born early.
• Why the injection and drops are not equivalent in protection.
• Comfort measures for the injection, such as skin-to-skin contact or feeding during it.

Feeding does not replace the vitamin: the AAP notes breast milk does not contain enough vitamin K to protect babies from VKDB.

The Egspect complete newborn care guide covers the other first-days checks, and our guide to the hepatitis B birth dose covers another newborn preventive decision you may meet in the first 24 hours.

When to call your midwife or doctor

VKDB can be a medical emergency. The NHS advises getting medical help straight away if your baby shows any of these:

• Easy or unexplained bruising, especially on the head or face.
• Bleeding from the nose, mouth, gums or umbilical cord stump.

Because late VKDB can cause bleeding inside the head, also treat these as urgent, and call emergency services (911 in the US, 999 in the UK) or go to emergency care:

• Seizures, or a baby who is unusually sleepy, hard to wake or floppy.
• Any sudden change in how your baby looks or behaves that worries you.

You do not need to be sure it is VKDB. If something seems wrong with your baby, trust that and make the call. For pregnancy-side warning signs, see pregnancy warning signs.

What you can do now

1. Check what your hospital or birth centre offers. Ask at an antenatal visit which vitamin K options are given and when, so you are not deciding for the first time in the delivery room.
2. Write down your questions for your midwife, obstetrician or paediatrician, including about your baby's risks.
3. Add your preference to your birth plan or tell your birth partner so they can speak up if you cannot.
4. If you have already declined or missed the shot, contact your paediatrician or health visitor promptly rather than waiting for the next routine check. Babies remain at risk up to 6 months.
5. Learn the bleeding warning signs above and keep your paediatrician's out-of-hours number to hand.
6. Keep your baby's vaccine and health records from the birth hospital, since the shot is recorded there.
7. Use our hospital bag checklist to make sure your papers and birth preferences go with you.

Sources and related reading

Official and primary sources:

• Wolf E, et al. JAMA Pediatrics, 2026 (DOI 10.1001/jamapediatrics.2026.5794), the study discussed above.
• American Academy of Pediatrics: Vitamin K helps prevent dangerous bleeding disorders in newborns.
• NHS: pregnancy and newborn care and East Kent Hospitals NHS Trust, Vitamin K for newborn babies.
• News peg: Medical Xpress report on the study.

Related Egspect guides and tools:

• Complete newborn care guide
• Hepatitis B birth dose for newborns
• Measles vaccine for babies
• Pregnancy warning signs
• Hospital bag checklist

This guide is general information, not medical advice. Facts were accurate as of November 6, 2026; guidance changes, so check with your care team.