U.S. Infant Bleeding Episodes Rise Amid Vitamin K Refusals

Two studies published on Thursday found a sharp rise in life-threatening bleeding episodes among U.S. infants since 2017, coinciding with an increase in parents refusing protective vitamin K shots at birth.

The studies are the first to show a correlation between rising vitamin K shot refusals and increased rates of infant bleeding. Vitamin K is essential for blood clotting, and newborns are not born with sufficient levels of the nutrient.

A Department of Health and Human Services spokesperson said the CDC still recommends vitamin K shots for newborns but declined to say whether the agency would begin tracking rates of vitamin K refusals or bleeding events.

A study published in JAMA last December found that more than 5% of U.S. 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.

Dr. Steven Woolf, an epidemiologist at Virginia Commonwealth University, noted that while the studies do not prove causation, the timing of increased bleeding episodes and vitamin K refusals is significant. He said the rate of bleeding events in 2025 was approximately double that of 2024.

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.