Two large studies published on November 5 report an association between declining vitamin K injections among U.S. newborns and increasing infant bleeding, including brain hemorrhages. The findings draw attention to parental refusal of a preventive treatment routinely administered after birth.
A research letter in JAMA Pediatrics examined approximately 11 million infants from 2017 through 2025. Vitamin K administration fell from 97.7% to 95%, while recorded cases of vitamin K deficiency bleeding nearly quadrupled.
A separate JAMA study involving 5.2 million infants found refusal rates rose from 3.1% to 6.8% over the same period. Infants who did not receive the injection had a 47% higher risk of bleeding and more than twice the risk of intracranial bleeding.
Additional Truveta data indicate that nonreceipt increased from 5.2% in January 2026 to 8.1% in June, suggesting the trend continued beyond the studies’ observation period.
Vitamin K supports blood clotting, and newborns naturally have low levels. The injection is a nutrient supplement, not a vaccine. Without sufficient vitamin K, infants can experience bleeding in the brain, digestive tract, or other organs. Late-onset deficiency bleeding can occur up to six months after birth, sometimes without warning. The shot reduces the risk of late-onset bleeding by approximately 98%.
Experts quoted in the report attribute rising refusals partly to vaccine hesitancy, medical distrust, and misinformation circulating online. Pediatrician Graham Tse also cited conflicting public health messages as a potential source of parental confusion. These explanations represent expert assessments rather than causes established by the studies.
Tse said some parents mistake the injection for vaccination. He described vitamin K as an established preventive treatment and urged parents to accept it at birth. The report states that the CDC recommends newborn vitamin K administration, while emphasizing that refusal can leave infants vulnerable to serious and potentially fatal bleeding complications.