The Vitamin K Shot: What the “Black Box Warning” Really Means for Newborns

The claim: An Instagram Reel by @thedailymomma03 (2026) claims that the newborn vitamin K shot carries a “black box warning” and that Merck’s version causes sudden infant death syndrome (SIDS). 

What the literature says: Vitamin K injections carry a boxed warning, but it concerns rare, severe allergic reactions, mostly reported with intravenous use (Merck & Co., 2002). The same label recommends a single intramuscular dose of 0.5 to 1 mg for each newborn, compared with 2.5 to 25 mg for adults, according to the American Academy of Pediatrics. It does not mention SIDS (Merck & Co., 2002). I searched CINAHL and MEDLINE (via EBSCO), as well as PubMed, and found no studies linking vitamin K injections to sudden infant death syndrome (SIDS). The scientific literature therefore contradicts the claim. 

The evidence for the shot is strong. Babies are born with low vitamin K, which puts them at risk for vitamin K deficiency bleeding (VKDB) (Ng & Loewy, 2018, p. 736). VKDB develops in infants who lack enough vitamin K to support clotting (Centers for Disease Control and Prevention [CDC], 2013, p. 901). The Canadian Paediatric Society and the College of Family Physicians of Canada recommend one intramuscular dose for every newborn (Ng & Loewy, 2018, p. 738). Infants who do not receive it are estimated to be 81 times more likely to develop late VKDB (CDC, 2013, p. 901). 

Public health implications: In 2013, Tennessee identified four cases of late VKDB in babies 6 to 15 weeks old whose parents had declined the shot. Three of them had bleeding in the brain (CDC, 2013, p. 901). Research shows that refusals are climbing, with U.S. newborns not receiving vitamin K nearly doubling from 2.92% in 2017 to 5.18% in 2024 (Scott et al., 2026, p. 272). This trend is not limited to the U.S. BORN Ontario (2026) reports that hospitals across the province are seeing more families decline the shot. 

This reel is effective because “black box warning” sounds official, and linking the shot to SIDS taps into one of parents’ deepest fears. The result is that parents may skip a safe, one-time shot to avoid a risk that does not exist, while leaving their baby exposed to a dangerous one. For health care professionals and health promoters, this means having honest conversations with parents before birth. That includes acknowledging what the warning label says, so misinformation does not fill the gap.

References

BORN Ontario. (2026, June 3). Rising vitamin K refusal in Ontario. https://www.bornontario.ca/news/posts/rising-vitamin-k-refusal-in-ontario/

Centers for Disease Control and Prevention. (2013). Notes from the field: Late vitamin K deficiency bleeding in infants whose parents declined vitamin K prophylaxis — Tennessee, 2013. Morbidity and Mortality Weekly Report, 62(45), 901–902. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6245a4.htm

Merck & Co. (2002). AquaMEPHYTON (phytonadione) injection [Package insert]. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2003/012223orig1s039lbl.pdf

Ng, E., & Loewy, A. D. (2018). Position statement: Guidelines for vitamin K prophylaxis in newborns: A joint statement of the Canadian Paediatric Society and the College of Family Physicians of Canada. Canadian Family Physician, 64(10), 736–739. https://pmc.ncbi.nlm.nih.gov/articles/PMC6184976/

Scott, K., Miller, E., Culhane, J. F., Greenspan, J., Handley, S. C., Lo, J. Y., Knake, L. A., McKenney, K. M., Burris, H. H., & Dysart, K. (2026). Trends in vitamin K administration among infants. JAMA, 335(3), 272–274. https://doi.org/10.1001/jama.2025.21460

thedailymomma03. (2026, August 26). Vitamin K black box warning- Merck causes SIDS [Video]. Instagram. https://www.instagram.com/p/Dcgvb7VoJnk/