Diagnoses of vitamin K deficiency bleeding among American infants have nearly quadrupled in under a decade, according to a new study in JAMA Pediatrics. Over the same period, a growing number of parents have turned down the single injection that has protected newborns from this bleeding since 1961.
The study does not prove that one caused the other. Even so, the pattern has alarmed paediatricians, because vitamin K deficiency bleeding (VKDB) can strike a healthy-looking baby with no warning and cause brain damage or death.
What the new study found
Researchers examined electronic health records of more than 11 million infants aged six months and younger. All were born at 35 weeks of gestation or later, and the records came from health systems using the Epic record platform.
The rate of VKDB diagnoses climbed from 24 per 100,000 infants in 2017 to 107.4 per 100,000 in 2025, an increase of about 347%. Diagnoses of vitamin K deficiency itself rose by roughly 216%. During the same years, the share of newborns recorded as receiving the injection fell from 97.7% to 95%.
Among infants diagnosed with VKDB, 123 (about 2.4%) also had a recorded diagnosis of bleeding in or around the brain.
| Measure | 2017 | 2025 |
|---|---|---|
| VKDB diagnoses per 100,000 infants | 24 | 107.4 |
| Newborns recorded as receiving the vitamin K shot | 97.7% | 95% |
| Overall change in VKDB diagnosis rate | About +347% |
The authors were careful about what the numbers can and cannot say. They stressed that the study cannot prove falling shot use caused the rise, though other factors known to contribute to vitamin K deficiency did not seem to explain the trend.
A second study points the same way
A companion study from the Children’s Hospital of Philadelphia, also published in JAMA, looked at who is missing the shot. It found that the share of babies not receiving vitamin K at birth more than doubled, from 3.1% in 2017 to 6.8% in 2025. Between 2024 and 2025 alone, it rose by about 20%.
Babies who missed the shot fared worse in several ways:
- They had a 47% higher risk of any bleeding event in the first six months of life.
- Their risk of any type of brain bleeding more than doubled.
- Their risk of dying during the birth hospitalisation more than doubled.
Reuters reported that the two studies were the first to show US infant bleeding rates rising alongside shot refusals.
More recent data suggests the trend may be speeding up. A Truveta analysis of 1,026,375 infants, posted as a preprint that has not yet been peer reviewed, found non-receipt averaged about 2.1% from 2019 to 2022. It reached 4.3% in 2025 and 6.1% in 2026. By June 2026 the monthly figure had climbed to 8.1%, up from 5.2% in January.
| Source | What it measured | Finding |
|---|---|---|
| CHOP study (JAMA) | Newborns not receiving vitamin K | 3.1% (2017) to 6.8% (2025) |
| Truveta analysis (preprint) | Non-receipt by month | 5.2% (Jan 2026) to 8.1% (Jun 2026) |
| AAN review (April 2026) | Refusal in most US hospitals, earlier years | Under 1% |
The figures differ between studies because they draw on different hospital networks and define non-receipt differently. The direction, though, is the same in every one.
Why newborns need vitamin K at all
Vitamin K helps the blood clot, and babies are born with very little of it. Several things work against them at once: little of the vitamin crosses the placenta, the liver holds small reserves, breast milk contains low amounts, and the newborn gut has not yet built the bacteria that make vitamin K naturally.
Protection can last until a baby starts eating solid foods richer in the vitamin, usually around six months. That is why the American Academy of Pediatrics has recommended a single shot after birth for more than 60 years. Prior research cited in the new study found it cuts late VKDB by 98%.
The three kinds of VKDB
| Type | When it appears | What to know |
|---|---|---|
| Early | Within 24 hours of birth | Often linked to maternal factors, such as certain medicines the mother takes |
| Classical | Days 2 to 7 | Can show as bleeding from the umbilical cord or gut |
| Late | 2 weeks to 6 months | Most dangerous; often arrives as a brain bleed in a baby who looked well |
The CDC says infants without the shot are 81 times more likely to develop life-threatening bleeding in the brain or gut during their first six months. It estimates that without the shot, such bleeding occurs in about one of every 59 births. About one in five babies who develop VKDB dies. Of those with late VKDB, about half have bleeding in the brain, which can cause permanent damage. Survivors face a heavy burden, with roughly two in five suffering long-term neurological harm in one clinical summary.
“Often, by the time we figure out that bleeding is happening, it’s really too late,” one doctor told ABC News, describing why prevention matters so much. There are frequently no warning signs.
Why are some parents saying no?
Doctors interviewed by ABC News pointed to several reasons. Some parents worry about pain, others about preservatives in the injection, and others have absorbed misinformation. An Idaho paediatrician said some families refuse it as part of a wider rejection of newborn examinations, fearing the process “creates trauma.”
An April review presented at the American Academy of Neurology found that risk factors for refusal included home birth, midwife care and “natural” philosophies. Parents who declined vitamin K were also much more likely to decline the hepatitis B vaccine and eye prophylaxis.
Some of the fear traces back to a 1992 study suggesting a link between the shot and childhood cancer. The claim was later debunked, and studies since then have found no such link. In the early 1980s, some hospitals in England had stopped routine vitamin K, and cases of VKDB reportedly rose afterwards.
Doctors are quick to point out that vitamin K is not a vaccine. It is a supplement. The main side effect is local redness or irritation at the injection site.
What about oral vitamin K?
Oral vitamin K exists, and some countries use it. A Swiss study covering 2018 to 2024 found that a three-dose oral schedule, given at four hours, day four and week four, remains a valid option for healthy infants. It also found that parental refusal and unrecognised liver bile-flow problems (cholestasis) remain the main risk factors for VKDB.
US doctors are more cautious. They note that oral vitamin K must be given repeatedly over several weeks, and that nobody can be sure how much a baby absorbs. The authors of the JAMA Pediatrics study suggested that offering oral vitamin K as a second choice could be considered if refusals keep rising, while acknowledging it may be less effective at preventing late bleeding.
| Injection | Oral doses | |
|---|---|---|
| Number of doses | One, soon after birth | Several over weeks |
| Dependence on parents | None after birth | High, missed doses leave gaps |
| Absorption certainty | High | Uncertain |
| Expert view in the US | Recommended standard | Possible fallback for refusers |
The policy picture
In June, Representative Kim Schrier of Washington and Senator Angela Alsobrooks of Maryland urged the CDC to start tracking VKDB cases. A Department of Health and Human Services spokesperson told Reuters that the CDC still recommends the shot, but would not say whether the agency would begin tracking refusals or bleeding events. Without national tracking, researchers have had to piece the picture together from hospital records.
What parents should do
Parents who have questions about the shot are urged to raise them early, ideally in the last weeks of pregnancy, with an obstetrician, midwife or paediatrician. One CHOP physician compared the shot to a seatbelt: a small precaution that matters enormously on the rare day it is needed.
Parents of any newborn should seek urgent medical care for unusual bleeding or bruising, bleeding from the umbilical cord stump or after circumcision, blood in the stool, a baby who is unusually sleepy or hard to wake, or repeated vomiting. This is general guidance, not a substitute for advice from your own doctor.
Vitamin K prophylaxis is routine in newborn care in many countries. Parents elsewhere, including in Nigeria, can simply ask their birth attendant whether it is given and when.
