01/12/2026
Let's Talk Vitamin K
Why is it important?
Vitamin K Deficiency Bleeding (VKDB) is a condition that can occur in exclusively breastfed newborns due to low levels of vitamin K, which is essential for proper blood clotting. There are different types and causes of VKDB, as well as different options for vitamin K supplementation after birth.
Types of Vitamin K Deficiency Bleeding:
The most common form of VKDB is idiopathic, meaning the cause is unknown.
Another form is secondary VKDB, which is usually related to maternal medication use during pregnancy. This can include medications such as blood thinners or certain seizure medications.
VKDB is also categorized based on when it occurs:
Early VKDB: Occurs within the first 24 hours after birth
Classic VKDB: Occurs between 2–7 days after birth. This timeframe is when vitamin K levels are naturally at their lowest in newborns
Late VKDB: Occurs from one week up to six months of age
Early/Classical VKDB occurs in as little as 1 in 60 births up to 1 in 250 births when Vitamin K is not given. Late VKDB is the rarest form (1 in 14,000 to 1 in 25,000 births if not given vitamin K), but it is also the most serious and carries the highest risk if it occurs.
Why Newborns Are Low in Vitamin K:
Vitamin K1 does not transfer efficiently through the placenta, which contributes to low vitamin K levels at birth. Additionally, vitamin K2 is produced by bacteria in the digestive tract, but newborns do not yet have an established microbiome. This microbiome develops gradually as babies consume breast milk and later solid foods.
There are two main options for vitamin K administration:
Oral Vitamin K:
Oral vitamin K is often chosen because it is non-invasive. When administered correctly with weekly dosing, it can reduce the risk of VKDB to approximately 1 in 100,000.
However, if oral vitamin K is not administered correctly, there is no reliable data on its effectiveness. Issues are more commonly seen due to inconsistent dosing or absorption problems.
In the United States, oral vitamin K is not FDA approved and is not regulated. This means parents need to carefully research the source, ensure the product is third-party tested, and verify ingredient quality.
Absorption of oral vitamin K may be affected if the baby:
-Spits up or vomits after dosing
-Has diarrhea
-Has undiagnosed liver or gallbladder conditions
These factors can reduce how well oral vitamin K is absorbed and increase risk.
Vitamin K Injection:
The vitamin K injection is the preferred option because it provides consistent dosing. It also contains a component that delays the release of vitamin K, helping maintain protective levels over the full six-month period during which late VKDB can occur.
Compared to babies who have the Vitamin K shot at birth, babies who are not given any Vitamin K treatment are 81 times more likely to develop VKDB, while babies who are given oral Vitamin K drops are 13 times more likely (Study done by McNinch & Tripp 1991).
Common Concerns and Misconceptions:
Some believe that a gentle or non-traumatic birth eliminates the need for vitamin K. There is no research to support this. Since VKDB can occur up to six months after birth, birth experience alone does not eliminate risk. All babies need vitamin K regardless of how their birth occurred.
Another concern is that vitamin K causes jaundice. Extensive research shows that vitamin K does not cause jaundice. Causes of jaundice can include:
-Rh blood incompatibility
-Bruising during birth
-Prenatal medications
-G6PD gene
-Large babies born to mothers with gestational diabetes
-Down syndrome
-Inadequate breast milk intake
-Infections
-Liver or gallbladder disease
-Prematurity
There is also discussion around a “black box warning.” This warning refers to allergic reactions. There is only one recorded case of the current vitamin K formulation used in the United States causing an allergic reaction in an infant. This warning primarily applies to larger doses given to adults, not the newborn dose.
Formula Feeding and Vitamin K:
Babies who are formula-fed do not always require additional vitamin K, as formula is fortified with vitamin K.
Final Thoughts:
Overall, it is recommended that babies receive some form of vitamin K—whether through injection, oral supplementation, or formula feeding—to reduce the risk of Vitamin K Deficiency Bleeding. This decision is ALWAYS left up to the parents. Here at Your Birth Story, I want parents to know the risks and benefits so When it comes time to make that decision you are making an informed decision.
For more information and specific studies on vitamin K deficiency bleeding as well as comparisons between the injection and oral vitamin K, parents can visit Evidence Based Birth at the following link:
https://evidencebasedbirth.com/evidence-for-the-vitamin-k-shot-in-newborns/
