Newborns Who Skip the Vitamin K Shot Face 47% Higher Bleeding Risk, Children's Hospital of Philadelphia Study Finds
Children's Hospital of Philadelphia announced on Nov. 5 that its researchers have published the largest retrospective study of its kind in the Journal of the American Medical Association, finding that more newborns are going without the routine intramuscular vitamin K shot at birth — and that this is linked to a higher risk of bleeding in infancy. The study analyzed 5.2 million infants born at 35 to 43 weeks across all 50 states and Washington, D.C., from 2017 to 2025, and followed them through six months of age.
The share of newborns who did not receive vitamin K rose from 3.1% in 2017 to 6.8% in 2025, more than doubling; in total, 234,825 newborns, or 4.5%, did not receive the shot. Babies who missed the shot had 288 bleeding events per 10,000 infants in their first six months, versus 186 per 10,000 among those who received it; after adjusting for gestational age, sex, maternal characteristics, insurance status and community factors, the group that skipped the shot faced a 47% higher risk of bleeding. For intracranial hemorrhage, the rates were 33 per 10,000 versus 13 per 10,000 — more than double. The study estimates one additional bleeding event for every 114 newborns who skip the shot.
Heather Burris, a neonatologist at Children's Hospital of Philadelphia and one of the study's authors, said vitamin K injections have effectively prevented vitamin K deficiency bleeding for decades, and urged better education for families about the serious and preventable risks of declining the shot. First author Christian Scott, now at Emory University School of Medicine, conducted the research during a postdoctoral fellowship at the hospital.
(Source: Children's Hospital of Philadelphia)
Source: Children's Hospital of Philadelphia
Published by GSM · USA (original Chinese edition)
Photo: 图：费城市政府大楼。（GSM 固定图库） / Photo: Philadelphia city government building.
