This nationwide Swedish cohort study evaluated trends in newborn intramuscular (IM) vitamin K prophylaxis refusal and its association with bleeding diagnoses in the first 6 months of life, covering 2,020,302 live births from 2003–2021 (≥35 weeks' gestation).
Infants who did not receive IM vitamin K had **1.52× higher odds of any bleeding** (aOR 1.52; 95% CI 1.27–1.81) and **2.91× higher odds of intracranial hemorrhage** (aOR 2.91; 95% CI 2.13–3.96). The rate of non-receipt doubled from 0.66% in 2006 to 1.50% in 2021 after an initial decline.
- Observational design limits causal inference; residual confounding possible. - Only IM vitamin K records were analyzed; oral prophylaxis use (if any) could not be distinguished from true non-receipt. - Findings reflect the Swedish healthcare context and may not generalize to settings with different refusal patterns or oral vitamin K protocols.
Parental refusal of IM vitamin K is rising and carries a nearly 3-fold higher risk of intracranial hemorrhage — clinicians should proactively counsel families on this safe, highly effective intervention. Continued parent and caregiver education is critical to reversing the uptick in refusals.
