Understanding the Risk of Vitamin K Deficiency Bleeding

December 7, 2025 •

2 min read

According to the Centers for Disease Control and Prevention (CDC), the risk of severe vitamin K deficiency bleeding (VKDB) is significantly higher in newborns who do not receive a prophylactic vitamin K shot at birth. This condition can cause serious and, in some cases, fatal bleeding if not addressed promptly.

Quick Summary

This summary details the causes, types, and symptoms of vitamin K deficiency bleeding, particularly in newborns and high-risk adults. It explains risk factors like exclusive breastfeeding and medical conditions, and emphasizes the importance of preventive measures to avoid severe bleeding complications.

Key Points

Newborns are at high risk: Low vitamin K stores from birth, a sterile gut, and low levels in breast milk make newborns highly susceptible to VKDB.
Prophylaxis is key for infants: A single intramuscular vitamin K shot given at birth is the most effective way to prevent VKDB in newborns.
Adult risk factors exist: Chronic diseases affecting fat absorption, liver disorders, and certain medications increase the risk of vitamin K deficiency in adults.
Symptoms can be subtle yet serious: VKDB in infants can present with severe intracranial bleeding without obvious warning signs, while adults may experience easy bruising and mucosal bleeding.
Bleeding is the main symptom: Uncontrolled bleeding is the primary manifestation of vitamin K deficiency, which can lead to life-threatening hemorrhage in severe cases.
Diagnosis is based on clotting time: Blood tests that measure how quickly blood clots, such as PT/INR, are used to diagnose vitamin K deficiency bleeding.
Treatment involves vitamin K supplementation: Administering vitamin K, via injection or orally, is the primary treatment for correcting the deficiency and stopping bleeding.

What is Vitamin K Deficiency Bleeding (VKDB)?

Vitamin K deficiency bleeding (VKDB), also known as hemorrhagic disease of the newborn, occurs when insufficient vitamin K leads to uncontrolled bleeding. Vitamin K is essential for the liver to produce vital blood-clotting factors. Without adequate levels, blood cannot clot effectively, increasing the risk of life-threatening hemorrhage.

The Role of Vitamin K in the Body

Vitamin K acts as a co-factor for an enzyme that modifies proteins necessary for blood coagulation. Both vitamin K1 from leafy greens and K2 from gut bacteria are important for this process.

Risk of VKDB in Newborns and Infants

Newborns are highly susceptible to VKDB because they have limited vitamin K stores at birth, their gut lacks vitamin K-producing bacteria, and breast milk contains low levels. A single intramuscular vitamin K shot at birth is highly effective at preventing VKDB.

Risk of VKDB in Adults

While uncommon in healthy adults, vitamin K deficiency can affect individuals with certain medical conditions or those on specific medications. Conditions that hinder fat absorption or affect liver function are key risk factors.

Common adult risk factors include:

Chronic health conditions: Diseases like cystic fibrosis, celiac disease, and liver disorders.
Medications: Certain antibiotics and blood thinners.
Nutritional deficiencies: Conditions involving malnutrition or extremely low-fat diets.

How the Risk Differs Between Neonates and Adults


Feature	Newborns and Infants	Adults
Primary Risk Factor	Low placental transfer and minimal vitamin K stores at birth.	Underlying medical conditions affecting absorption or metabolism.
Typical Onset	Within the first six months of life, especially weeks 2-8 for late-onset VKDB.	Often related to chronic illness, medication, or liver disease.
Prevention	Routine intramuscular vitamin K shot immediately after birth.	Managing underlying health issues, dietary modification, or supplementation.
Severe Complication	Severe intracranial hemorrhage, which can lead to brain damage and death.	Increased risk of bleeding, osteoporosis, and cardiovascular disease.

Symptoms and Diagnosis of VKDB

Symptoms of VKDB vary from minor bruising to severe internal bleeding.

Common infant symptoms include:

Excessive bruising.
Bleeding from umbilical cord or circumcision site.
Nosebleeds.
Bloody stools or vomit.
Pale skin or jaundice.
Signs of brain bleeding in severe cases.

Adults may experience easy bruising, nosebleeds, and gastrointestinal bleeding. Diagnosis involves blood tests to measure clotting time, such as PT and INR. PIVKA-II tests are used in infants.

Treatment and Prevention of VKDB

Prevention and timely treatment are crucial. Newborns receive a prophylactic vitamin K shot. If bleeding occurs, vitamin K injections are given. Severe cases may require blood transfusions. In adults, managing the underlying cause and potentially using dietary changes or supplements are key.

Conclusion

Vitamin K deficiency bleeding carries a significant risk, particularly for newborns, but can also impact adults with specific risk factors. Routine vitamin K prophylaxis for newborns is a highly effective preventive measure. For adults, managing health conditions and being aware of medication effects are important for prevention. Recognizing symptoms allows for prompt intervention and helps prevent severe complications.

Frequently Asked Questions

VKDB is a bleeding disorder that occurs in infants due to insufficient levels of vitamin K, a critical nutrient for blood clotting. Newborns are naturally deficient at birth and need supplementation to prevent potentially fatal hemorrhages.

Newborns are at risk because they have low vitamin K reserves from limited placental transfer, their sterile intestines cannot yet produce the vitamin, and breast milk contains low amounts. This creates a high risk of bleeding in the first few months of life.

The most effective prevention is a single intramuscular vitamin K injection administered shortly after birth. This dose provides enough vitamin K to the infant until their diet and gut bacteria can provide an adequate supply.

For infants who do not receive the vitamin K shot, the risk of developing late-onset VKDB is estimated to be significantly higher. This can result in life-threatening intracranial hemorrhage, leading to brain damage or death.

Adults with conditions that cause fat malabsorption, such as cystic fibrosis, celiac disease, and liver or biliary disease, are at increased risk. Chronic antibiotic use and malnutrition also play a role.

Symptoms in adults often include easy bruising, mucosal bleeding like nosebleeds, bleeding from a wound, blood in urine or stool, and sometimes internal gastrointestinal hemorrhage.

In cases of mild deficiency, a diet rich in vitamin K (from leafy greens, oils, eggs, and cheese) might be sufficient. However, for severe deficiency or conditions causing malabsorption, supplementation via oral doses or injection is often necessary.