By Julie Steenhuysen
CHICAGO, Nov 5 (Reuters) - Rates of life-threatening bleeding in US infants have risen sharply since 2017 as parents increasingly refuse protective newborn doses of vitamin K, a trend that coincides with a growing wave of mistrust toward vaccines and other newborn interventions, two studies published on Thursday found.
The studies are the first to show that bleeding rates in US infants have increased along with rising refusals of vitamin K shots.
Babies are not born with enough
vitamin K, an essential nutrient that helps blood clot, and vitamin K injections at birth have been standard for over 60 years. As a result, the US Centers for Disease Control and Prevention does not track rates of vitamin K refusals or bleeding.
Vitamin K refusals have been rising steadily since the COVID-19 pandemic, but have accelerated under Health Secretary Robert F. Kennedy Jr., who spent decades sowing mistrust about vaccines before taking the nation's top health post. He has since dropped childhood recommendations for six vaccines. Changes to the childhood vaccination schedule are on hold over a legal challenge. Health experts say the mixed messages have raised doubts among many parents about routine newborn treatments, including vitamin K.
The US Department of Health and Human Services did not immediately respond to a request for comment on the studies.
A study published in JAMA last December by Dr. Kristan Scott and colleagues at the Children's Hospital of Philadelphia showed that more than 5% of US babies did not receive a vitamin K shot in 2024, a 77% increase since 2017.
The latest data, published in JAMA and JAMA Pediatrics, show rates of vitamin K refusals have continued to climb, and begin to connect the dots between rising refusals of the essential vitamin and increased bleeding episodes.
While these studies do not prove causation, the fact that the rates of bleeding have increased so dramatically at the same time vitamin K refusals and deficiencies have risen is significant, said Dr. Steven Woolf, an epidemiologist at Virginia Commonwealth University, whose study appeared in JAMA Pediatrics.
Providing vitamin K shots at birth has been the standard of care since 1961. "Now we're stepping away from that and we're seeing the consequences," he said.
Woolf and colleagues studied medical records from 11 million infants six months and younger between 2017 and 2025. During that time, the percentage of newborns who received a vitamin K shot fell from 97.7% to 95%, while the rate of vitamin K deficiency bleeding nearly quadrupled and appeared to be accelerating.
Of more than 11 million births, there were a total of 5,217 bleeding events over that multi-year period.
"The rate in 2025 was approximately double what it was in 2024," Woolf said.
The team noted that the peak in 2025 coincides with eroding trust in public health following the COVID pandemic, rising vaccine hesitancy and growing parental skepticism around newborn interventions.
An exclusive analysis for Reuters of more than 1 million births nationwide by health data and analytics company Truveta found the percentage of vitamin K refusals accelerated sharply in the first half of 2026, jumping by more than 57% from January through June.
In Scott's new study, published in JAMA, the team analyzed medical records on more than 5.2 million US infants born between 2017 and 2025.
During that time, the rate of newborns who did not receive a vitamin K shot more than doubled to 6.8% in 2025 from 3.1% in 2017. It also jumped from the 5.1% refusal rate at the end of 2024.
Babies who did not receive a vitamin K shot had a 47% higher risk of bleeding within the first 6 months of life compared with babies who did.
They also had more than twice the risk of bleeding in the brain in their first six months, and death with a bleeding diagnosis during their hospital stay after birth.
The authors calculated that for every 114 newborns who do not receive a vitamin K shot at birth, one additional bleeding event would occur.
In June, Representative Kim Schrier of Washington and US Senator Angela Alsobrooks of Maryland, both Democrats, called on the CDC to start tracking these bleeding events.
Dr. Elizabeth Wolf, a pediatrician at Children’s Hospital of Richmond, who led the VCU study, said the findings call for clear messages from all levels of public health about the need for vitamin K.
“Similar to the recent measles outbreaks, we are seeing the real-world implications of growing mistrust of doctors and public health professionals," she said.
(Reporting by Julie SteenhuysenEditing by Caroline Humer and Bill Berkrot)
