Vitamin K is an essential vitamin that the body requires for normal bone development, vascular health, and — most pertinent to this topic — a healthy blood clotting system.
Vitamin K is found in abundance in green leafy vegetables, many fruits and berries, chicken and oils such as soybean, olive and canola oil. The body also produces its own vitamin K with the help of normal gut bacteria once babies begin eating a balanced diet beyond breast milk or formula.
Thankfully, vitamin K deficiency is quite rare — except in newborns. Very little vitamin K crosses the placenta during pregnancy, so all infants begin life with very low vitamin K stores.
These stores remain low for several months, especially in exclusively breastfed infants because breast milk naturally contains only small amounts of vitamin K. Infant formula contains more vitamin K than breast milk, but it is still not an adequate amount for several days, which is why supplementation at birth is recommended regardless of feeding method.
Although persistent vitamin K deficiency can contribute to long-term health problems, the most immediate and dangerous consequence is bleeding. Before routine vitamin K prophylaxis, early and classic Vitamin K Deficiency Bleeding occurred in approximately 0.25–1.7% of newborns (roughly 1 in 400 to 1 in 60 births), depending on the population studied.
Intracranial hemorrhage was among the most devastating complications, often occurring without warning and carrying a high risk of death or permanent neurologic injury. Since universal vitamin K administration at birth became standard practice, VKDB has become exceedingly rare in countries with high uptake of the newborn vitamin K injection.
Hemorrhagic disease of the newborn, now known as VKDB) was first recognized in the late 1800s, but the cause was not understood until the 1930s when a Danish biochemist identified vitamin K’s critical role in blood clotting.
Shortly afterward, a Swedish researcher conducted a study involving more than 13,000 newborns demonstrating that vitamin K supplementation immediately after birth dramatically reduced hemorrhagic disease. That study included both oral and intramuscular administration.
While both reduced early-onset VKDB, oral vitamin K proved less reliable because it requires multiple doses and was significantly less effective at preventing late-onset VKDB.
As a result, in 1961 the American Academy of Pediatrics officially recommended a single intramuscular vitamin K injection for every newborn shortly after birth, and it has remained the standard of care ever since.
Although oral vitamin K protocols exist for parents who decline the injection, they require multiple doses over several weeks, depend on perfect adherence and still do not provide the same protection against late VKDB. We also know that maternal vitamin K supplementation during pregnancy does not prevent VKDB because only minimal amounts cross the placenta.
VKDB is classified into three forms:
• Early onset: within the first 24 hours after birth.
• Classic: from 24 hours through the first week of life.
• Late onset: from 2 weeks to 6 months of age.
This distinction is important because the risk does not end when a newborn leaves the hospital. Babies who do not receive the single IM dose remain vulnerable for months.
Unfortunately, these life-threatening bleeds rarely give warning signs before they occur. Approximately one in five infants with VKDB dies, and about half of late-onset cases involve bleeding into the brain. Among survivors of intracranial hemorrhage, approximately 40% suffer permanent neurologic injury or developmental disabilities.
Another early bleeding complication that is sometimes overlooked is elective newborn circumcision.
Vitamin K deficiency significantly increases the risk of serious bleeding following newborn circumcision, which is why many hospitals and nurseries will not perform an elective circumcision unless the infant has received the vitamin K injection.
Since this has been the standard of care for more than 60 years and has prevented countless cases of severe bleeding and death, why are we still discussing it today?
Much like vaccines, concerns about the vitamin K injection increased after a small study published in England in 1990 suggested a possible association with childhood cancer. Numerous larger, better-designed studies conducted since then have found no evidence that the vitamin K injection increases the risk of childhood leukemia or any other childhood cancer.
Unfortunately, the original claim continues to circulate on social media despite being thoroughly disproven.
Thankfully, deaths from VKDB remain rare, because most newborns still receive vitamin K at birth. However, as more parents decline this simple, safe and highly effective intervention, preventable cases continue to occur.
The newborn vitamin K injection is one of the safest and most effective preventive interventions in modern medicine. A single injection provides protection during the months when babies are naturally most vulnerable to vitamin K deficiency bleeding, preventing a rare but potentially devastating condition that can cause lifelong disability or death.
Dr. Mindy Frimodig is a family physician at ThedaCare Medical Center-Shawano and a member of the Shawano Community Health Action Team.
