Rates of life-threatening bleeding in U.S. infants have increased significantly since 2017, coinciding with a growing trend of parents refusing protective newborn doses of vitamin K, according to two studies published on Thursday. This rise in refusals and bleeding incidents is occurring amid a broader wave of mistrust toward vaccines and other standard newborn interventions.
Babies are born with insufficient vitamin K, a nutrient crucial for blood clotting. Vitamin K injections have been a standard practice for newborns for over 60 years. However, the U.S. Centers for Disease Control and Prevention does not currently track rates of vitamin K refusals or infant bleeding events.
One study, led by Dr. Kristan Scott and colleagues at the Children’s Hospital of Philadelphia and published in JAMA, analyzed medical records for over 5.2 million U.S. infants born between 2017 and 2025. During this period, the rate of newborns not receiving a vitamin K shot more than doubled, climbing from 3.1% in 2017 to 6.8% in 2025. Infants who did not receive the vitamin K shot showed a 47% higher risk of bleeding within their first six months of life, with more than double the risk of brain bleeds and a higher risk of death with a bleeding diagnosis during their hospital stay.
The authors calculated that approximately one additional bleeding event occurs for every 114 newborns who do not receive vitamin K at birth.
A separate study, published in JAMA Pediatrics and conducted by Dr. Steven Woolf and colleagues at Virginia Commonwealth University, examined medical records for 11 million infants six months and younger between 2017 and 2025. This research found that the percentage of newborns receiving a vitamin K shot decreased from 97.7% to 95% over the study period. Concurrently, the rate of vitamin K deficiency bleeding nearly quadrupled and showed signs of acceleration, with the rate in 2025 approximately double that of 2024.
"Now we’re stepping away from that and we’re seeing the consequences," said Dr. Woolf, an epidemiologist at Virginia Commonwealth University. His team noted that the increase in bleeding events aligns with declining trust in public health institutions, exacerbated by the COVID-19 pandemic and rising vaccine hesitancy.
An analysis of over one million births nationwide by health data company Truveta revealed that the rate of vitamin K refusals accelerated sharply in the first half of 2026, increasing by more than 57% from January through June.
Health experts suggest that mixed messages and skepticism surrounding newborn interventions have contributed to these trends. In June, Representatives Kim Schrier and Senator Angela Alsobrooks urged the CDC to begin tracking these bleeding events. Dr. Elizabeth Wolf, a pediatrician who led the VCU study, emphasized the need for clear public health messaging on the importance of vitamin K, stating, "Similar to the recent measles outbreaks, we are seeing the real-world implications of growing mistrust of doctors and public health professionals."