US newborn vitamin K refusals doubled as bleeding risk climbed
Why it matters: A study of 5.2 million infants found 1 in 114 babies who skipped the shot developed bleeding within six months.
Parents in the United States are increasingly refusing vitamin K shots for newborns, and a large new study linked that rise to more dangerous bleeding cases and higher death risk during birth hospitalizations. The share of infants who did not receive the injection climbed to 6.8% in 2025 from 3.1% in 2017, according to research published in JAMA. Tracking 5.2 million infants in all 50 states, researchers found babies who missed the shot faced a significantly higher risk of bleeding by 6 months old, including in the brain and gastrointestinal tract. Vitamin K shots have been used universally since 1961 to prevent a deficiency that can be fatal in about 20% of cases.