Key Takeaways
- In a study of 5.24 million US newborns, the share who did not get the vitamin K shot rose from 3.1% in 2017 to 6.8% in 2025.
- Babies who missed the shot had a 47% higher adjusted risk of bleeding by six months — about 102 extra cases per 10,000 births — and more than double the risk of bleeding in the bra
- The study is observational: it proves a strong association, and it cannot separate documented parental refusal from other reasons a shot was missed.
More Newborns Are Missing the Vitamin K Shot. The Bleeding Risk Is Higher.
A simple injection given shortly after birth has helped protect newborns from dangerous bleeding for decades. But more babies are now going without it.
A study tracking 5,240,780 infants born at 35 to 43 weeks across all 50 US states found that the share who did not receive the vitamin K shot more than doubled between 2017 and 2025 — rising from 3.1% to 6.8%.
In total, 234,825 babies missed the injection.
What Happened to Babies Who Missed the Shot?
The difference showed up in bleeding cases.
By six months of age, babies who did not receive the shot experienced bleeding at a rate of 288.0 per 10,000 births, compared with 185.9 per 10,000 among babies who received it.
After adjusting for other factors, the risk was 47% higher. Researchers estimated that for every 114 babies who went without the injection, there was one additional bleeding case.
The findings were even more concerning for bleeding inside the brain. Its adjusted risk was more than twice as high (adjusted risk ratio 2.43). Deaths during the birth hospitalization with a bleeding diagnosis were also higher.
There are important caveats. This was an observational study of health records, so it shows an association, not proof of cause and effect. The records also show that the shot was not given, not whether parents formally refused it or something else went wrong.
The absolute risk for an individual baby remains small, but the growing number of babies missing the injection makes the trend difficult to ignore.
Health note: This article summarizes a research study and is not medical advice. If you are expecting a baby and have questions about the vitamin K shot, raise them with your doctor or midwife before delivery, when there is time to talk them through.
The Twikup Take
A 47% higher relative risk can sound abstract when the underlying numbers are small. But the direction of the findings matters: more newborns are missing a preventive injection, and those babies are experiencing more bleeding, including inside the brain.
Parents deserve clear information about both the benefits of the vitamin K shot and the risks of going without it — before making that decision.
Image: AI-generated illustration.