New Evidence
Why the vitamin K shot?
5.2 million US newborns, rising refusal, and what happened to infants who did not get vitamin K at birth.
Source: Scott K, et al. JAMA. Published online November 5, 2026.
The question
Refusal of newborn vitamin K prophylaxis has been rising in the US. How common is nonreceipt now, and how does it relate to bleeding in the first six months?
The study
- Retrospective cohort using the Epic Cosmos dataset, with hospitals and health systems in all 50 states.
- 5,240,780 infants born at 35 to 43 weeks' gestation between 2017 and 2025.
- Exposure: no recorded intramuscular vitamin K at birth. Primary outcome: bleeding within 6 months, identified by ICD-10 codes. Relative risks were adjusted for covariates.
What they found
3.1% → 6.8%Nonreceipt, 2017 to 2025
aRR 1.47Any bleeding by 6 months
aRR 2.43Intracranial bleeding
- Nonreceipt of vitamin K rose from 3.1% of births in 2017 to 6.8% in 2025.
- Bleeding by 6 months: 288.0 vs 185.9 per 10,000 in infants who did not vs did receive vitamin K (adjusted risk ratio 1.47; 95% CI 1.43–1.51).
- Intracranial bleeding: 33.0 vs 13.2 per 10,000 (aRR 2.43; 95% CI 2.26–2.62).
- Death with concurrent bleeding during the birth hospitalization: 2.9 vs 1.1 per 10,000 (aRR 2.69; 95% CI 2.09–3.47).
- Bleeding incidence by 6 months rose over the study period in both groups: from 225.3 to 394.0 per 10,000 without vitamin K, and from 136.6 to 221.8 per 10,000 with it.
Where the evidence stops
- This is an observational study. It shows an association, not proof that every bleed was vitamin K deficiency bleeding.
- Bleeding was identified from diagnosis codes in health records, not from case-by-case confirmation.
- Families who decline vitamin K may differ in other ways. A 2026 scoping review found that refusal often occurs alongside refusal of other newborn interventions.
- Only infants born at 35 weeks or later were included.
References
- Scott K, Handley SC, Lo JY, et al. Nonreceipt of Newborn Vitamin K and Risk of Bleeding. JAMA. Published online November 5, 2026. doi:10.1001/jama.2026.21764 · PubMed 42986716
- Kang A, Martin J, Chu D, Bailey A. Refusal of Intramuscular Vitamin K among Newborns by Parents: A Review of Recent Literature. Acad Pediatr. Published online November 6, 2026. doi:10.1016/j.acap.2026.103739 · PubMed 42994687
Independent educational content, not medical advice. Not affiliated with or endorsed by the AAP. Summaries reflect the published papers; read the originals before changing practice.
