Vitamin K is a fat-soluble vitamin that facilitates the production of proteins necessary for blood clotting. Its concentration in breast milk often raises questions for new parents about whether their infant is receiving an adequate supply from breast milk alone.
Why Newborns Have Low Vitamin K Levels
A primary reason for low vitamin K in newborns is the minimal transfer of the vitamin across the placenta during pregnancy. Vitamin K does not pass efficiently from mother to fetus, meaning babies are born with very small reserves. These stores are insufficient during the first weeks of life.
The newborn’s digestive system also contributes to this low-level status. In older children and adults, vitamin K is synthesized by beneficial bacteria in the gut. A newborn’s gut is nearly sterile at birth and it takes several weeks for these bacterial colonies to become established and begin producing vitamin K. Due to these factors, the low levels of vitamin K in breast milk are not enough to compensate for the infant’s limited stores.
The Risk of Vitamin K Deficiency Bleeding
The primary concern with insufficient vitamin K is a condition known as Vitamin K Deficiency Bleeding, or VKDB. This disorder is characterized by spontaneous bleeding due to the blood’s inability to clot properly. VKDB is categorized into three forms based on when the bleeding occurs after birth.
Early-onset VKDB happens within the first 24 hours of life and is rare, often associated with certain maternal medications. Classical VKDB occurs between the first and seventh day of life. Bleeding may be seen from the umbilicus, in the gastrointestinal tract, or following procedures like circumcision.
Late-onset VKDB appears between the second week and sixth month of life. It can manifest without warning in infants who appear healthy, with up to half of cases involving intracranial hemorrhage, or bleeding in the brain. This form is most commonly seen in exclusively breastfed infants who did not receive vitamin K supplementation at birth.
Supplementation Methods for Breastfed Infants
To prevent all forms of VKDB, a single intramuscular injection of vitamin K is the standard of care recommended by organizations like the American Academy of Pediatrics. This shot, containing a 1 mg dose for infants over 1500g, is administered within six hours of birth. This single dose is effective at providing a sufficient supply of vitamin K through the first months of life.
An alternative to the injection is an oral vitamin K regimen. This method, however, requires multiple doses to be effective. A common schedule involves administering doses at birth, again at three to five days, and a third dose at four weeks for breastfed babies. The effectiveness of oral vitamin K can be compromised by factors such as inconsistent absorption in the infant’s gut or if the baby spits up a dose. For these reasons, the injection remains the most reliable method for ensuring adequate protection.
Maternal Diet’s Influence on Vitamin K
Many breastfeeding mothers wonder if they can increase their infant’s vitamin K levels through their own diet. While consuming foods rich in vitamin K, such as leafy greens like spinach and kale, can modestly increase its concentration in breast milk, this increase is not substantial enough to protect an infant against VKDB. The amount of vitamin K that passes into breast milk remains relatively low even with maternal supplementation.
Therefore, changes in the maternal diet are not considered a reliable substitute for direct vitamin K supplementation for the newborn. Pediatric health organizations stress that either the vitamin K shot or a complete oral dosing schedule is necessary to ensure the baby has adequate levels for blood clotting. A mother’s focus on a healthy diet supports her own health and the overall quality of her milk, but direct supplementation for the baby is the recognized standard for preventing VKDB.