US study of 11 million infants: vitamin K deficiency diagnoses up 216% in 2017–2025 as shots decline
Diagnoses of vitamin K deficiency and related bleeding rose as the share of US newborns receiving the injection fell from 97.7% to 95.0%, a JAMA Pediatrics study reports.
A nationwide study of electronic health records in the United States found that diagnoses of vitamin K deficiency (VKD) and vitamin-K-deficient bleeding (VKDB) in infants rose by 216% and 347%, respectively, between 2017 and 2025, SciTechDaily reports. Over the same period, the share of newborns receiving injectable vitamin K fell from 97.7% to 95.0%. The work, led by Elizabeth Wolf of Children's Hospital of Richmond at VCU, was published on November 5, 2026, in JAMA Pediatrics. scitechdaily.com
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Data and findings
The researchers analyzed de-identified electronic health records from a large national database covering health systems across the United States. The analysis included more than 11 million infants aged 0 to 6 months, born at 35 weeks' gestation or later, who received care between 2017 and 2025.
Only 40% of infants diagnosed with VKD and about 19% of those diagnosed with VKDB had received vitamin K shots. About 7% of infants with VKD and 2% of those with VKDB also had a diagnosis of intracranial or intracerebral hemorrhage. Earlier studies found that the proportion of newborns who did not receive intramuscular vitamin K rose from 2.9% in 2017 to 5.2% in 2024.
The authors caution that the simultaneous decline in injections and increase in diagnoses does not prove causation. Wolf considers other explanations unlikely, because behaviors and diseases that raise the risk of VKD remained constant or decreased during the study period.
Why newborns need vitamin K
Vitamin K activates proteins needed for normal blood clotting. Newborns receive too little through the placenta, absorb it poorly through the digestive system, and get little from breast milk. The American Academy of Pediatrics has recommended one intramuscular dose for newborns since 1961. scitechdaily.com
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Classical VKD occurs between 2 days and 1 week after birth and causes bruising and bleeding from the umbilicus. Late VKD, which occurs between 1 week and 6 months of age, carries a 30% to 60% risk of intracranial hemorrhage, which can lead to seizures, permanent brain damage, or death.
Wolf said more research is needed to understand why parents refuse the injection and how best to communicate the seriousness of the deficiency. The authors note that rates of VKD and VKDB may continue to rise if refusal keeps increasing.
