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Skipping the Newborn Vitamin K Shot: What 288 vs 186 Bleeds per 10,000 Means

ByLife Choice Note

Short answer: In a US cohort study published in JAMA on November 5, 2026, infants without a record of intramuscular vitamin K at birth had 288.0 bleeding diagnoses per 10,000 by age 6 months, compared with 185.9 per 10,000 among infants who received the injection. The adjusted relative risk was 1.47. Because this was an observational analysis of electronic health records, it cannot prove that vitamin K nonreceipt caused every recorded bleed.

Publication date: November 5, 2026 · Region: Epic Cosmos hospitals and health systems across all 50 US states · Population: hospital-born infants delivered at 35 to 43 weeks’ gestation from 2017 through 2025 · Reviewed: November 8, 2026

What did the study compare?

The researchers analyzed electronic records for 5,240,780 infants. Of these, 234,825 had no record of receiving intramuscular vitamin K during the birth hospitalization, while 5,005,955 had a recorded dose.

The primary outcome was any bleeding diagnosis through age 6 months. It was a composite built from diagnosis codes for intraventricular hemorrhage, intracranial hemorrhage, newborn hemorrhage, gastrointestinal hemorrhage and vitamin K deficiency bleeding. The headline rate therefore is not a count of confirmed vitamin K deficiency bleeding alone.

What does 288 vs 186 per 10,000 mean?

Bleeding was recorded in 288.0 per 10,000 infants without vitamin K and 185.9 per 10,000 infants who received it. After adjustment for factors including sex, gestational age, birth size, maternal age, insurance, community vulnerability and year, the relative risk was 1.47.

The adjusted absolute risk difference was about 87.5 per 10,000. The investigators calculated an adjusted number needed to harm of 114: within this dataset and model, one additional infant bleeding diagnosis was associated with every 114 newborns who did not receive the injection. This is a population estimate, not a prediction that identifies which individual infant will bleed or why.

What about bleeding in the brain?

Intracranial or intraventricular bleeding was recorded in 33.0 per 10,000 infants without vitamin K and 13.2 per 10,000 with vitamin K, for an adjusted relative risk of 2.43. Death during the birth hospitalization with a concurrent bleeding diagnosis occurred in 2.9 vs 1.1 per 10,000.

The mortality result needs particular caution: the number of events was small, and the records could not establish whether bleeding occurred before death or directly caused it. Looking only at the period after discharge through age 6 months, bleeding was recorded in 10.3 vs 4.8 per 10,000, with an adjusted relative risk of 2.11.

Did nonreceipt become more common?

Within the included health systems, the proportion of newborns without recorded vitamin K increased from 3.1% in 2017 to 6.8% in 2025. Bleeding diagnoses also rose in both groups over time. The researchers could not fully determine whether changes in detection, coding, patient mix or other clinical factors contributed to that trend.

What are the study’s limits?

  • It was not a randomized trial. Unmeasured differences between families and infants could affect both vitamin K receipt and bleeding risk.
  • The outcome came from diagnosis codes. Exact timing, severity, cause and confirmation of vitamin K deficiency were not consistently available.
  • Infants born before 35 weeks were excluded. The estimates should not be applied directly to more premature infants.
  • Home births and birth centers were underrepresented. Bleeding treated outside participating systems could also be missed.
  • Oral vitamin K was not captured. Neither was an intramuscular dose given after discharge.
  • These are US data. Absolute rates may differ in other countries and health systems.

How does this fit current guidance?

The US Centers for Disease Control and Prevention explains that newborns begin life with very small vitamin K stores and that breast milk contains little vitamin K. A one-time intramuscular dose after birth is the most reliable way to prevent vitamin K deficiency bleeding. This study did not test a new injection schedule; it examined the association between nonreceipt and bleeding in a large real-world dataset.

Parents with questions about ingredients, timing or alternatives can raise them with the maternity and newborn care team before delivery. A newborn with active bleeding, extensive bruising, pallor, poor feeding, unusual sleepiness, seizures or other concerning symptoms needs urgent medical assessment; an online article cannot determine the cause.

Primary sources

Prepared by: Life Choice Note, an independent personal health-information explainer. This article provides general information and does not diagnose illness or replace individualized newborn care.

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