Cases of infant bleeding surged last year as more parents refused critical vitamin K injections for their newborns, according to new research released Thursday in JAMA Pediatrics.
While the research does not point to a cause, scientists note some of the change comes during a time of growing skepticism around public health fueled partly in recent years by President Donald Trump’s administration.
Cases of vitamin K-deficient bleeding have increased most years since 2017 and spiked last year, according to the study.
“We’ve gone generations without seeing this kind of increase in complications,” said Steven Woolf, a professor of family medicine and population health at Virginia Commonwealth University and a co-author of the study. “It’s very disheartening to see that progress in public health rolling back.”
Department of Health and Human Services spokesperson Grace Jamison said in a statement that the Centers for Disease Control and Prevention “recommends that parents give newborns a vitamin K injection within 6 hours of birth to prevent vitamin K deficiency bleeding.”
The statement acknowledged that uptake of the dose has declined in recent years and that “public trust in health care institutions has fallen,” but blamed “heavy-handed mandates and inconsistent messaging during the Biden administration” amid the covid-19 pandemic.
Vitamin K helps the body form blood clots. Newborns don’t have enough of it at birth or receive enough from breastmilk, and their digestive systems are too immature to make it, said Elizabeth Wolf, an associate professor of pediatrics at Virginia Commonwealth University and lead author of the study.
Infants deficient in vitamin K are at risk of uncontrollable bleeding and strokes.
“Babies who have these vitamin K deficient strokes, 20 percent of them will die, and then of the survivors, 40 percent will have permanent neurologic problems,” Wolf said. “So it can be very, very serious.”
Yearly cases of vitamin K-deficient bleeding increased from 189 to 903 between 2017 and 2024, according to the study. Then last year, they nearly doubled. There were 1,764 cases of vitamin K-deficient bleeding in 2025. Of those cases, a majority of infants had not received vitamin K shots. A small percentage of the cases led to hemorrhages in the brain.
The study analyzed electronic health data of more than 11 million infants in the United States and also found that between 2017 and 2025, the percentage of infants receiving a vitamin K shot fell from 98 percent to 95 percent.
Researchers said the rise in cases of shot refusals and of bleeding incidents coincides with the growth of vaccine skepticism. At least in recent years, that has been further fueled by moves from the Trump administration to overhaul childhood vaccine schedules and an erosion of trust in public health guidance, they say.
“As scientists, we can’t prove causality,” Woolf said. “But 2025 was a year where we saw a real escalation by the administration in messaging that eroded public confidence in public health interventions.”
The vitamin K shot is not a vaccine, but doctors said some parents confuse it for one because it is given as an injection.
Skepticism toward the shots may have “ramped up since the covid vaccine came out,” said Howard Gill, chairman of the pediatrics department at Holy Cross Health in Fort Lauderdale, Florida, who was not involved in the study. “And it became more of a political conversation.”
Democratic lawmakers have accused Health Secretary Robert F. Kennedy Jr., who has not publicly supported vitamin K shots, of exacerbating the trend. Rep. Kim Schrier (D-Washing) and Sen. Angela Alsobrooks (D-Maryland) sent a letter to the CDC in June describing the shift as a “growing and preventable public health crisis” and calling on the agency to track refusals of vitamin K shots and vitamin K-deficient bleeding.
When asked by Schrier to support the shots in a House subcommittee meeting in April, Kennedy denied he was connected to the refusals and said “I’ve never said anything about vitamin K.”
HHS did not respond to questions about the letter to CDC or criticism of Kennedy.
Vitamin K can also be given orally, and some parents opt for this instead of an injection, Gill said. But it is not the standard treatment because it is considered less effective than an injection. Infants sometimes require multiple vitamin K doses if given orally.
Wolf and Woolf wrote in their study that offering vitamin K orally may nevertheless be warranted as a “harm-reduction approach” if parents continue to refuse injections.
“It’s a hard time to be a pediatrician right now,” Wolf said.
“Sometimes it’s difficult to convey … information to the family and have them trust you,” she said.
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