vitamin K for neonates

• neonates are typically born with low levels of vitamin K (1.2)
  • because some clotting factors in the blood plasma are dependent on vitamin K, vitamin K deficiency can cause bleeding in the neonate in the first hours to months of life
    • vitamin K deficiency bleeding (VKDB) in newborns is categorized based on the timing of presentation
      • early VKDB occurs within 24 hours after birth,
      • classic VKDB presents in the first week of life,
      • late VKDB occurs between 1 week and 6 months, with a peak incidence between 2 and 8 weeks
    • can be prevented by giving vitamin K to newborns

NICE advise vitamin K prophylaxis for newborns should be offered; and to to give vitamin K as an injection into the muscle because this is the method that is most efficacious (1):

• if parents do not want their baby to have vitamin K by injection, offer oral vitamin K as an alternative. Advise parents that oral vitamin K:
  • may need to be given as multiple doses, including after the baby goes home,
    and
  • should be given at the dose and time according to the manufacturer's
    instructions

Notes:

• factors associated with the development of vitamin K deficiency in newborns include:
  • poor placental transfer of vitamin K,
  • immature hepatic synthesis of vitamin K–dependent clotting factors (estimated at 30%-50% of adult levels),
  • a lack of intestinal colonization by vitamin K–producing bacteria
  • note that exclusive breastfeeding further increases risk, as breast milk contains relatively low concentrations of vitamin K

Reference:

1. NICE (June 2026). Intrapartum care.
2. Daley SF, Sina RE. Vitamin K Deficiency in Neonates and Adults. [Updated 2026 May 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-.