Newborn Vitamin K Shot: Babies Who Skip It Face a 47 Percent Higher Bleeding Risk, JAMA Study of 5.2 Million Infants Finds

Of everything that happens in the first hours of a baby’s life, the vitamin K shot is probably the least photogenic. Nobody posts it. Nobody frames it. It is a quick injection that has been routine in the United States since the 1960s and most parents barely remember it. Which is exactly why two new studies published on 5 November 2026 deserve your attention: they suggest that a growing number of babies are missing it and that this has measurable consequences.

We know a health story rarely competes with a celebrity campaign for clicks. This one is worth the extra minute, because it is about one of the simplest protective measures in medicine.

What the JAMA study found

The larger of the two studies appeared in JAMA. A team from Children’s Hospital of Philadelphia, led by Kristan Scott, who has since moved to Emory University School of Medicine, analysed electronic health records of 5.2 million infants born at 35 to 43 weeks of pregnancy between 2017 and 2025. The data came from hospitals and clinics in all 50 US states plus Washington, D.C.

The first finding is the trend. The share of newborns who did not receive the vitamin K injection more than doubled, from 3.1 percent in 2017 to 6.8 percent in 2025. Across the whole study period, 234,825 infants went without it.

The second finding is the cost. In the first six months of life, the researchers counted 288 recorded bleeding events per 10,000 births among babies without documented vitamin K, compared with 186 per 10,000 among those who received it. After adjusting for factors such as gestational age, insurance and neighbourhood characteristics, not receiving the shot was associated with a 47 percent higher risk of any recorded bleeding. For bleeding inside the skull, the gap was wider: 33 versus 13 per 10,000, more than twice the risk. Deaths with a bleeding diagnosis during the birth hospital stay were also more common, at 2.9 versus 1.1 per 10,000.

The researchers translated this into a number that is easier to picture: roughly one additional bleeding event for every 114 newborns who do not get the injection. “Our study is the first to document a nationwide decline in administration paired with increases in bleeding risks,” said co-author Heather Burris, a neonatologist at the hospital.

A second study points the same way

On the same day, JAMA Pediatrics published a research letter from Virginia Commonwealth University led by Elizabeth Wolf. Using a similar health record database covering about 11 million US infants, her team found that the share of babies receiving the injection fell from 97.7 percent to 95.0 percent between 2017 and 2025. Over the same period, diagnoses of vitamin K deficiency bleeding rose from 24.0 to 107.4 per 100,000 infants. Only 19.2 percent of the babies diagnosed with this type of bleeding had received the shot. The authors stress that their data show an association, not proof of cause.

A Swedish cohort of more than 2 million infants, also published in JAMA Pediatrics this year, reported a similar pattern, which makes it harder to dismiss the US findings as a quirk of one dataset.

Why newborns need vitamin K at all

Vitamin K is essential for blood clotting. According to the US Centers for Disease Control and Prevention, babies are born with very little of it, so even a minor injury can lead to serious bleeding in rare cases. The condition is called vitamin K deficiency bleeding. It is uncommon, but when it happens it can affect the brain and be life-threatening. That combination of rare and severe is precisely what makes prevention look unnecessary until the moment it is not.

Why parents say no

Health records cannot tell us why a shot was not given. Reporting earlier this year, based on accounts from providers, described common themes: parents who see the injection as unnatural or unnecessary, requests for oral drops instead and growing scepticism about routine care since the Covid pandemic. Influencers promoting unregulated vitamin K drops on social media have added to the confusion. An old worry also lingers: a British study from the 1990s suggested a possible link between the injection and childhood leukaemia, but most later research found no significant association.

“Natural” is a lovely word on a skincare label. For a newborn’s clotting system it is less reassuring. Kristan Scott put the stakes more bluntly in an interview earlier this year, describing opting out as “akin to gambling with a child’s health.”

What about oral vitamin K?

This is where the German perspective becomes interesting. In Germany, the standard scheme recommended by the nutrition commission of the German Society for Paediatrics and Adolescent Medicine is oral: three doses given at the U1, U2 and U3 check-ups in the first weeks of life. The German Drug Commission of the Medical Profession has documented a case of brain bleeding in an infant after incomplete prophylaxis, a reminder that the later doses matter too. If you have questions about the scheme for your child, your midwife or paediatrician is the right person to ask.

In the United States, there is no FDA-approved oral vitamin K product for newborns. An editorial accompanying the JAMA study, written by Laura Kair of UC Davis and colleagues, calls on clinicians and public health agencies to reinforce the injection recommendation. It also asks for better surveillance plus an FDA-regulated oral formulation for families who firmly decline the shot. Wolf’s team made a similar suggestion, arguing that an oral option as a second-line choice may be warranted if refusals continue.

The limits of the data

Both studies are observational. The JAMA analysis excluded babies born before 35 weeks as well as home births, could not tell whether some infants received oral vitamin K or a later injection and lacked detail on how severe each bleed was. The authors also note that clinicians may code bleeding more readily when they know vitamin K was withheld. Bleeding rates rose in both groups over the study period, which may partly reflect better detection.

Still, the excess risk among babies without vitamin K appeared in every year of the study. Taken together with the Swedish data and the VCU letter, the picture is consistent. The shot has become a victim of its own success: it worked so well for decades that its purpose faded from view. The next few years will show whether better communication, tighter monitoring and perhaps an approved oral alternative can bring it back into focus before more families learn its value the hard way.

This article is for general information only and does not replace medical advice. If you have questions about vitamin K or any other part of newborn care, please talk to your midwife, paediatrician or doctor.