It has been six years since I’ve posted anything on Vitamin K refusal – in 2014 I described it as the new anti-vax (though Clay provided a repost last November). Unfortunately it continues to be a problem for newborns, despite efforts at public education.

Why vitamin K?

Newborns lack sufficient vitamin K, largely because the vitamin does not easily cross the placenta. It also exists in low quantities in breast milk, and so babies may be deficient until around six months of age when they start to include other food in their diet. Vitamin K is necessary to form clotting factors, and so the primary risk of being deficient it an increased risk of bleeding, including spontaneous bleeding (i.e. not provoked by trauma or any external event), known as vitamin K deficient bleeding (VKDB). Bleeding can occur early, within the first week of life, or late, after the first week but within the first six months. According to a recent review:

Without prophylaxis, estimates of the incidence per 100 000 births of VKDB range from 250 to 1700 for early VKDB and from 10.5 to 80 for late VKDB.

The absolute risk is therefore low but still significant. The most common locations for VKDB in newborns is either the brain or the bowels. Bleeding in the brain can impair neurological development and even cause death. Intestinal bleeding can also be life-threatening. But worry not – one shot of intramuscular vitamin K at birth significantly reduces that risk (relative risk in that study was 0.19, with a number needed to treat of 74). The shot immediately increases vitamin K levels, with most of the vitamin being stored in the liver where it is slowly released over the next six months.

Medical interventions are all about risk vs benefit, so what are the potential risks of one IM shot of vitamin K at birth? The risks are actually minimal, and specific risks are rarely cited as reasons for refusal. There was one preliminary study showing a potential correlation between vitamin K shots and childhood cancer, but this correlation was later completely refuted by larger and more rigorous studies. I have only seen mention of it in resources, like this one, citing the evidence to refute a correlation. So unlike the myth that vaccines cause autism, this debunked correlation does not seem to be driving vitamin K refusal.

Right now the recommendation of the American Academy of Pediatrics and other medical organizations is for every newborn to receive one IM dose of vitamin K at birth. This ensures universal coverage for the first six months of life, it reduces the risk of VKDB and all the morbidity and mortality that results, and it is extremely safe. However, some still find reasons to refuse this safe and effective medical intervention.

Why people refuse vitamin K

In my original 2014 article I discussed a review of Nashville area hospitals conducted in 2013 which found that:

At hospitals, 3.0% of infants did not receive injectable vitamin K due to parental refusal in 2013, a frequency higher than in 2011 and 2012. This percentage was much higher at birthing centers, where 31% of infants did not receive injectable vitamin K. The most common responses for refusal were a belief that the injection was unnecessary (53%) and a desire for a natural birthing process (36%). Refusal of other preventive services was common, with 66% of families refusing vitamin K, newborn eye care with erythromycin, and the neonatal dose of hepatitis B vaccine.

Three percent is low, but that still represents a lot of potentially avoidable VKDB. The more concerning figure is the 31% in birthing centers who refuse. This may be due to self-selection of the type of parents who choose birthing centers, but there is concern that it also reflects the philosophy of the midwives and other practitioners at these centers. In a good 2019 article on the topic, pediatrician Rachel Pearson relates stories of patients told by their midwives not to get the vitamin K shot. We need good data on this practice, but the 31% figure is alarming in any case.

A 2020 review found essentially the same results:

The frequency of refusal of intramuscular vitamin K by parents ranged from 0% to 3.2% in US hospitals, up to 14.5% in home births, and up to 31.0% in birthing centers. Reported reasons for refusal were concern of harm from the injection, a desire to be natural, and a belief in alternative methods of prophylaxis. Parents who refused intramuscular vitamin K were more likely to refuse immunizations.

So essentially nothing has changed. The main reason for objection to vitamin K is not based in evidence or any solid logic, but is rather philosophical – the desire to be “natural”. This is a downstream effect of the appeal to nature fallacy that is ubiquitous in the marketing of alternative medicine. It also strikes me as interestingly selective. When CAM providers give high dose intravenous vitamins for their treatments, the vitamins are considered “natural” remedies, and the high doses justified. When doctors give an evidence-based dose of a needed vitamin with clear benefits, that is not “natural”.

The notion that the shot is “unnecessary” is a claim that is subject to facts. It is based in a misconception, that a healthy newborn without trauma does not need the vitamin K. On one “mommy” blog, the author explains their reasons for refusing vitamin K:

Yes, I believe there may be instances where a newborn may need it if there are bleeding issues, but my daughter was completely healthy and normal with no visible signs of trauma after coming out of the birth canal unassisted.

This is a myth. Otherwise-completely-healthy newborns without signs of trauma can still have VKDB. Also, by the time you notice the signs of a bleed, it’s too late, the (potentially catastrophic) damage is done. Yet again, there is selective use of logic here – CAM proponents market themselves (falsely) as being more focused on prevention. Well here is an evidence-based preventive measure, criticized for being preventive rather than reactive.

I point out these inconsistencies because what is at work here is not evidence and reason, but marketing and world-view. The important factor here is a lack of trust in the medical and scientific establishments, a lack of trust resulting from the CAM culture that is constantly beating the drum of paranoia and conspiracy theories. This is the result.

The alternative methods usually refers to oral vitamin K. So far there is no evidence-based oral regimen shown to work. There is evidence that single dose oral vitamin K is less effective than the IM shot. It is still an open question if multiple oral doses can be as effective as IM, but even if this does work the problem is compliance. You have to keep up with the regimen of oral doses. A single IM dose at birth, however, is all you need. So the real-world effectiveness of the single shot will always be better.

The evidence is crystal clear in this case – single dose IM vitamin K at birth is a very safe and effective method for preventive VKDB in newborns and infants. Objection to this effective intervention is based on misconceptions rooted in the alternative medicine marketing and philosophy, and spread mostly by non-physicians. We have to stay ahead of this phenomenon, and perhaps a dose of science-based information may be preventive.


Posted by Steven Novella

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics’ Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.