Protocols › Vitamin K

Vitamin K for newborn babies

Goal: What trials and doctors' groups used to prevent bleeding from vitamin K deficiency in the first weeks of life.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 3 Nov 2026
Dose

One dose of 1 mg, which a Cochrane review found effective.[1] The American Academy of Pediatrics advises 0.5 to 1 mg.[2]

Form

An injection into a muscle. Doses by mouth improved blood clotting tests, but the review found no randomized trial that tested them against bleeding.[1]

When to take

Once, soon after birth.[1][2]

How long

One dose. In trials, 3 doses by mouth gave higher vitamin K levels at 2 weeks and 2 months than one injection.[1]

What studies found

In 2 trials, one injection reduced bleeding in the first 7 days of life, including bleeding after circumcision.[1] The review found no randomized trial that tested it against late bleeding, at 2 to 12 weeks.[1] A 2018 review found no trial in preterm babies that compared vitamin K with no treatment.[3]

Ask a doctor first

Late bleeding can occur in babies who are only breastfed, because breast milk has little vitamin K. Babies with liver or gut problems, such as cholestatic jaundice or cystic fibrosis, are also at risk.[2] The only trial in a 2018 review of preterm babies gave 0.2 or 0.5 mg.[3]

Parents with questions about the dose or the way it is given should ask the baby's doctor or midwife.[2]

References

  1. Prophylactic vitamin K for vitamin K deficiency bleeding in neonates. Puckett RM, Offringa M Cochrane Database Syst Rev, 2000. PMID 11034761
  2. Vitamin K: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  3. Prophylactic vitamin K for the prevention of vitamin K deficiency bleeding in preterm neonates. Ardell S, Offringa M, Ovelman C, Soll R Cochrane Database Syst Rev, 2018. PMID 29401369