Two large U.S. studies find that vitamin K deficiency bleeding among infants is rising as more parents decline the routine newborn vitamin K injection. In one study of more than five million infants, refusal increased from 3.1 percent in 2017 to 6.8 percent in 2025; babies who missed the shot had higher bleeding rates in their first six months and more than twice the risk of brain bleeding. A second study, covering over 11 million infants, found that refusal more than doubled and recorded a nearly 350 percent rise in vitamin K deficiency bleeding, reaching 107.4 cases per 100,000. Cases roughly doubled between 2024 and 2025. The injection helps blood clot and prevents rare but potentially catastrophic bleeding in otherwise healthy newborns.
The studies offer substantial U.S. evidence linking declining use of the shot with worse outcomes, though their measures differ: one counted all infant bleeding, while the other counted cases attributed to vitamin K deficiency. Their databases omit many home births, where refusal is more common, and diagnosis may be more likely when clinicians know a baby missed the injection. The shot is not a vaccine and is considered very safe. Some parents reject it as unnatural or unnecessary, or cite social-media claims about preservatives and an alleged leukemia link; evidence does not support those concerns. Researchers and pediatricians hope the findings make the risks of refusal clearer.
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