Thread by @ENirenberg

A reminder: the birth dose of vitamin K is NOT a vaccine but is still critical to give within the first 6 hours following birth.

Here is why refusing this intervention is a really bad idea 🧵

Vitamin K is a fat-soluble vitamin that we can get from our diet (e.g., from leafy green vegetables) or from our own gut bacteria. Newborns however, cannot consume these foods and do not have gut bacteria to make vitamin K for them.

Further making things difficult here is that vitamin K does not easily cross the placenta (meaning all children are born deficient) and it does not readily end up in breastmilk. This is a BIG problem because vitamin K is absolutely required for the liver to make...

clotting factors. If vitamin K deficiency occurs, it can cause vitamin K deficiency bleeding (VKDB). When this occurred in babies it used to be called "hemorrhagic disease of the newborn" because it causes inappropriate bleeding. Newborns' livers also are not great at...

using vitamin K efficiently, which makes the fact that they have low reserves to start with particularly bad. This makes correcting their deficiency absolutely critical, which is why an intramuscular injection of vitamin K is recommended within 6 hours of birth.

Early and classical VKDB can occur as often as 1 in 60 to 1 in 250 live births. Late VKDB (see above) is much rarer at around 1 in 20,000 live births. There is no reliable way to predict which infants may get VKDB before it happens, though some risk factors are known.

Intramuscular vitamin K is shown to reduce the risk of vitamin K deficiency bleeding 81-fold (a very small number of babies can have conditions which prevent them from being able to effectively use vitamin K to make clotting factors, hence this is not 100% effective).

Many myths exist surrounding this intervention, so let's spend a moment on those. Some people express discomfort that the vitamin K must be delivered as a shot and point to oral supplementation, either during pregnancy or for the first few weeks of life. Unfortunately,...

while increasing consumption of vitamin K during pregnancy can increase concentrations of vitamin K transferred through the placenta, this is not clearly demonstrated to prevent VKDB. It is likely that the levels of vitamin K are still too low for solid protection.

As for orally supplementing infants, while this has been done in the past in some countries, it requires weeks of rigid adherence to a dosing schedule which is hard to do for sleep-deprived new parents. Also, more concerningly, oral vitamin K supplementation was not shown...

to prevent late VKDB which is particularly severe and can be fatal. Countries that switched to the intramuscular dose of vitamin K at birth, however, rapidly saw late VKDB disappear. There is also a US-specific issue in that if sold as a supplement, the regulation...

is very lax. A study in 2022 found that of 30 supplements marketed to boost the immune system, less than half even contained detectable quantities of their claimed active ingredient (and 9 had additional unreported ingredients):
jamanetwork.com/journals/jaman…

It is also worth mentioning that because vitamin K is fat-soluble, any conditions of fat malabsorption can interfere with correction of vitamin K deficiency by oral supplementation- but this concern does not apply to intramuscular vitamin K.

Another point has to do with the concern that vitamin K can cause inappropriate clots. There is literally a warning on the package insert for the product that states vitamin K cannot spontaneously induce clotting. Vitamin K only makes it possible to make clotting factors.

Clotting factors need to be processed from their inactive forms to clot, which doesn't happen spontaneously.
Some have also raised concerns about the dose (1 mg for all infants weighing at least 1500 grams, 0.3 to 0.5 mg/kg as a single, intramuscular dose for <1500 g per AAP).

The recommended daily allowance of vitamin K for a newborn infant is 2 μg (500 times less than the quantity inside a dose of vitamin K1 for a term infant). However, there are a few key facts to know here. Firstly, though the shot contains 1 mg, this does not mean that...

the dose behaves as an instant administration of 1 mg directly into the plasma. The intramuscular vitamin K forms a depot which slowly releases vitamin K into the circulation wherein it can reach the liver. Secondly, though vitamin K is a fat-soluble vitamin, meaning...

in principle, it can build up to toxic levels, in practice this is not true. Vitamin K turnover in the liver is extremely rapid. There is in fact no established tolerable upper limit for vitamin K in the way that there is for other vitamins precisely because of this.

In the past, Menadione, a naturally occurring form of vitamin K3, was used for supplementation and at higher doses did have associated toxic effects wherein it could cause reactive oxygen species generation that killed and damaged liver cells. However, this form of...

vitamin K is no longer used for supplementation.
Some have also raised concerns about. Preservatives are there to prevent contamination which could result in catastrophic infection if injected. The tiny quantities of benzoyl peroxide present in each dose...

of vitamin K have not been associated with any known harms at the quantities they are present in the dose. However, preservative-free forms of vitamin K are available as well if this is really a sticking point (though it shouldn't be).

I could go on as there are many more myths but the upshot is this: the birth dose of vitamin K is a nearly risk-free intervention that can prevent rare but potentially catastrophic harms to infants. It is the standard of care and has been since 1961 in the US.

There are no data to date that merit reconsideration of that standard. The AAP in fact reaffirmed it just last year:

publications.aap.org/pediatrics/art…

I implore new parents to ensure their infants are protected from VKDB. The vitamin K shot for newborns is critical.

I will also add that I am happy to do my best to address good-faith concerns about this and vaccines but at a certain point it’s very hard to remain detached from the reality that misinformation about these things is quite literally killing innocent people and the awareness of…

The gap between the effort it takes to espouse complete nonsense by a person who has no idea what they’re talking about and the time it takes to show why they’re wrong is extremely taxing and demoralizing. We can correct misinformation but we can’t revive the dead.

Also I’m just blocking anyone who doesn’t engage in good faith, but to sum up a recurring theme:

- yes, all babies need vitamin K
- yes, your babies were born deficient
- no, your babies didn’t have VKDB because it’s relatively rare and they got lucky

- yes, this used to be a major source of morbimortality in infancy before we started supplementation and it’s well-documented throughout history.

karger.com/neo/article-ab…

- your refusal of vitamin K isn’t a feather in your cap as a parent, or an endorsement for your critical thinking skills. You refused an intervention that quite literally has nearly 0 risk and prevents life-threatening complications like intracranial hemorrhage.