Single intramuscular vitamin K injection is recommended for all newborns shortly after birth to prevent a dangerous and potentially fatal bleeding disorder known as vitamin K deficiency bleeding (VKDB).
Newborns Need Vitamin K because of low stores at birth: Vitamin K does not easily cross the placenta during pregnancy, so babies are born with very minimal amounts in their bodies.
Insufficient breast milk levels: Breast milk contains very low concentrations of vitamin K, and exclusively breastfed infants cannot build up adequate levels on their own.
Immature gut bacteria: Healthy adults get vitamin K from foods and gut bacteria, but newborns do not yet have the intestinal bacteria needed to produce it naturally until they begin eating solid foods at around 4 to 6 months of age.
Without proper clotting factors activated by vitamin K, infants are vulnerable to Vitamin K Deficiency Bleeding, which can cause sudden, internal bleeding in the intestines or the brain:
Early-onset VKDB: Occurs within the first 24 hours of life, often related to medications the mother took during pregnancy.
Classical VKDB: Occurs between 2 days and 1 week after birth (presenting as bruising or umbilical bleeding).
Late-onset VKDB: Occurs between 1 week and 6 months of age.
Roughly half of these cases involve bleeding inside the brain, which can lead to permanent brain damage, seizures, or death.
Infants who do not receive the injection face an increased risk of developing late-onset VKDB.
How It Is Given
The Injection: is a single intramuscular injection administered in the thigh muscle, usually within the first 6 hours of birth.
Oral vitamin K drops or pills are available in some regions, but they are less reliable, require multiple repeated doses, and do not protect as effectively against late-onset brain bleeding because newborns absorb the oral form poorly.
The vitamin K shot is not a vaccine. It is a safe, plant-derived nutrient supplement, with minor side effects restricted to brief localized pain, redness, or swelling at the injection site.