Vitamin K

Vitamin K injections as standard care for newborns has come under public scrutiny recently. Largely because of misunderstanding and misapplication of information. Influencers repeat bad information and build mistrust.

Much of the concern and ultimate rejection of this standard infant treatment comes down to fear. Fear is not a good mindset to have when making decisions. So let's break it down.

What is it? Why do babies need it?

• Vitamin K is necessary for baby’s body to make several clotting factors (things that slow down bleeding).
  

• Vitamin K levels are so low in cord blood as to be undetectable.
  

• Breastmilk contains only small amounts of vitamin K which don’t meet infant requirements.

  Vitamin K in breastmilk is affected by your diet, but only to a limited extent. While eating vitamin K-rich foods can slightly increase its presence in milk, the dietary amount needed is 800% higher than the safe limit for consumption.  

  
  

• Vitamin K is not synthesized by the type of bacteria in the infant gut.
  

The Problem

• Vitamin K Deficiency Bleeding can result (>24 hours to 6 months)
  

• Incidence is very low, however, this is based on recent high levels of treatment at birth.
  

• At birth, vitamin K-dependent clotting factor levels are 30–50% of adult.
  

• Without Vitamin K supplementation, levels do not truly stabilize during the first 6 months of life
  

Items in italics are most common form of initial presentation.

• Bleeding may occur in one or multiple areas:   

  • oozing from umbilicus (belly button)

  • cephalohematoma (swelling on the head from birth)

  • bleeding circumcision site

  • GI bleed (may see bloody or black stools)

  • oral bleeding

  • skin bruising

  • bleeding from injection sites

  • internal bleeding

  • intracranial (brain) bleed
    

• Seemingly insignificant bleeds (“warning bleeds”) or subtle weight faltering may precede the emergency

Recommended Treatment

• 1 mg vitamin K SQ (injection) in the first day of life, response is rapid in about 4–6 hours

  
  

  Some parents question of oral Vit K can be given in place of an injection but there are several problems with this regime.
  

• There is no licensed oral form in the US.  Some have given infants the injectable liquid by mouth, but this is unstudied -- there is no safety or effectiveness data available.
  

• Since multiple doses are required for oral treatment, failures (even with good compliance) have been reported.  Failures have not been reported with IM (injectable) treatment.
  

• Oral vitamin K is rapidly absorbed, produces a high but short peak in levels, and then is quickly cleared. 

  
  

  Injectable Vit K is slowly released from the injection site over an extended period, maintaining elevated serum levels for weeks to months for longer term protection.

Let's address some of the concerns and online rumors.

Does vitamin K cause cancer?

• One study published in the British Medical Journal in 1990 raised this concern, suggesting that the risk of cancer was doubled in babies who received vitamin K at birth.

• Many studies since then in Europe and in US have refuted this claim and found no association between the two.

• There is good consensus among experts that IM (injectable) vitamin K prophylaxis is safe and is not associated with childhood cancer.

  
  

Does vitamin K cause jaundice ?

• There were reports of hemolytic anemia and hyperbilirubinemia (jaundice) severe enough to cause kernicterus in the mid-1950s with high doses (50mg) of vitamin K2 (menadione).   As a result, use of this form of vitamin K was abandoned.  We now give infants vitamin K1 (phytonadione).  
  

• Vitamin K1 has been associated with hyperbilirubinemia only in extremely high doses (25–30mg). This has not been a problem when vitamin K1 is given in normal therapeutic doses (0.5-1mg).

What other side effects have been reported?

• Anaphylaxis, though most common after IV infusion, has rarely been reported with injection.
  

• Scleroderma-like patch at the site of injection has been reported primarily in adults after repeated injections, though there are reports of 7 infants with similar dermatologic reactions (again, millions of doses are given without problems).

What does this have to do with breastfeeding? The biggest issue I've seen as an IBCLC is that newborns who do not receive prophylaxis Vit K have a delay in frenotomy treatment for tongue tie. You can't get the injection outpatient and the majority of release providers won't perform the procedure if baby only receives oral Vitamin K as the effectiveness is so variable (and like it was shared above, the regime takes multiple doses over time). This has resulted in delayed care for babies, maternal nipple damage, and more complex feeding plans including more pumping and bottle feeding (with the added burden of time to double feed plus cleaning for bottles and parts).

References

American Academy of Pediatrics, Committee on Fetus and Newborn.  Controversies Concerning Vitamin K and the Newborn.  Pediatrics 2003 July; 112(1):191-2.

Clarke P, Shearer MJ, Card DJ, et al. Exclusively Breastmilk-Fed Preterm Infants Are at High Risk of Developing Subclinical Vitamin K Deficiency Despite Intramuscular Prophylaxis at Birth. Journal of Thrombosis and Haemostasis: JTH. 2022.

Cornelissen, M., et al.  Prevention of vitamin K deficiency bleeding: efficacy of different multiple oral dose schedules of vitamin K.  Eur J Pediatr.  1997 Feb; 156(2):126-30.

Greer, FR, et al. Improving the vitamin K status of breastfeeding infants with maternal vitamin K supplements. Pediatr. 1997 Jan;99(1).

Hand I, Noble L, Abrams SA. Vitamin K and the Newborn Infant. Pediatrics. 2022.

Kindberg C, Suttie JW, Uchida K, Hirauchi K, Nakao H. Menaquinone Production and Utilization in Germ-Free Rats After Inoculation With Specific Organisms. The Journal of Nutrition. 1987.

Hertli S, Zimmermann P. Molecular interactions between the intestinal microbiota and the host. Molecular Microbiology. 2022.

Ramotar K, Conly JM, Chubb H, Louie TJ. Production of Menaquinones by Intestinal Anaerobes. The Journal of Infectious Diseases. 1984.

Ross, JA, Davies SM. Vitamin K prophylaxis and childhood cancer. Med Pediatr Oncol. 2000 Jun;34(6):434-7.

Simatou E, Tsamantioti E, Hallström A, et al. Vitamin K Prophylaxis in Newborns and Bleeding in Infancy. JAMA Pediatrics. 2026.

Smajdor J, Jedlińska K, Porada R, et al. The Impact of Gut Bacteria Producing Long Chain Homologs of Vitamin K on Colorectal Carcinogenesis. Cancer Cell International. 2023.

Standford Medicine. Information About Vitamin K Prophylaxis. Clinical Guidelines. Reviewed 07/2026

Toulon P, Berruyer M, Brionne-François M, et al. Age Dependency for Coagulation Parameters in Paediatric Populations. Results of a Multicentre Study Aimed at Defining the Age-Specific Reference Ranges. Thrombosis and Haemostasis. 2016.

Witt M, Kvist N, Jørgensen MH, Hulscher JB, Verkade HJ. Prophylactic Dosing of Vitamin K to Prevent Bleeding. Pediatrics. 2016.