Deep Dive: Skipping Newborn Vitamin K Shot Linked to 47% Higher Bleeding Risk

Parenting · 8 November 2026

A large JAMA study of more than 5.2 million US infants found that the share of newborns who did not receive the routine intramuscular vitamin K shot more than doubled from 3.1% in 2017 to 6.8% in 2025. Those infants faced a 47% higher risk of any bleeding event in the first six months and more than twice the risk of intracranial bleeding.

Background

Vitamin K deficiency bleeding (VKDB) has been known for decades. Newborns have low vitamin K stores, limited gut bacteria to produce it, and low transfer from the placenta or breast milk. Without the shot, classic and late-onset VKDB can cause serious internal or brain bleeding. The American Academy of Pediatrics has recommended a single intramuscular dose at birth since 1961. The shot is cheap, highly effective, and has an excellent safety record.

What changed

Researchers at Children’s Hospital of Philadelphia analyzed Epic Cosmos data covering births from 2017 through 2025. Nonreceipt rose steadily and accelerated. Infants without documented vitamin K had:

A parallel analysis of roughly 11 million infants showed vitamin K deficiency bleeding nearly quadrupling over the same period. Authors calculate that one additional bleeding event occurs for every 114 infants who do not receive the shot.

Competing viewpoints

Some parents decline the shot because of concerns about pain, preservatives, or a general preference to avoid interventions. A few online communities have incorrectly linked vitamin K to later autism or other outcomes—claims not supported by evidence. Others prefer oral vitamin K regimens used in some countries, though those require multiple doses and have higher failure rates for late VKDB.

Pediatric groups, including the AAP, continue to recommend the single intramuscular dose as the most reliable protection. The rise in refusals tracks broader declines in childhood vaccination rates and increased parental skepticism toward routine newborn care.

What to watch next

Parents deciding about the vitamin K shot should discuss the documented bleeding risks with their pediatrician or neonatologist. The shot remains one of the simplest, highest-yield protections available in the first hours of life.

Sources: JAMA (Scott et al., November 2026), Children’s Hospital of Philadelphia, Reuters, MedPage Today, FDA alerts on toddler snack bars.