Vitamin K Refusal Rates Have Doubled, and Infant Brain Hemorrhage Is Preventable
Every newborn is physiologically deficient in vitamin K at birth, and a single intramuscular shot drops the risk of late bleeding to near zero; but US refusal rates have risen from 3% to 5.8%, and babies whose parents refuse face 81 times the risk of late bleeding.
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Every newborn is born deficient in vitamin K
Vitamin K does not cross the placenta effectively, so even if the mother supplements during pregnancy, the newborn's vitamin K-dependent clotting factors do not rise appreciably. Add an immature gut microbiome and very little self-synthesized K2, and breast milk averaging only about 2.5 micrograms per liter, and an exclusively breastfed infant takes in less than 1 microgram a day for the first six months. The result is that every newborn is at high risk of vitamin K deficiency bleeding. This is not an outlier phenomenon; it is the physiological norm.
— Erin Allman-UpdykeLate bleeding often comes with no warning, straight to brain hemorrhage
Vitamin K deficiency bleeding in newborns comes in three types: early, within 24 hours of birth; classic, within the first week; and late, from one week to six months. Late is the most dangerous: about 60% of cases are intracranial hemorrhage, and there is often no warning bleed beforehand, just sudden brain hemorrhage, seizures or unresponsiveness. Mortality ranges from 50% to 60% depending on era and country, with modern figures around 20%. That is why the value of a single preventive shot cannot be measured by "the bleeding probability is low."
— Erin Allman-UpdykeOne intramuscular shot pushes the risk to near zero
Since 2003 in the US, and in the vast majority of medical societies and public health agencies worldwide, a single intramuscular vitamin K shot at birth is recommended. It provides a stable supply through the first few months, cutting late bleeding risk from 4 to 7 cases per 100,000 live births (some countries report as high as 80) to about 0.4. Infants who receive no prophylaxis have 81 times the risk of late bleeding compared with those who do. Oral regimens also significantly reduce risk, but they require multiple doses, are affected by absorption and vomiting, and are less effective than injection, and the US has no regulator-approved oral formulation.
— Erin Allman-UpdykeHow a 1950s overdose scandal destroyed trust
In the postwar research climate, informed consent and patient protections had not yet entered the picture, and the logic was "vitamin is harmless and possibly beneficial, so give it to all premature infants." In the mid-1950s Britain gave some premature infants up to 60 milligrams of synthetic vitamin K, after which jaundice, hemolysis and kernicterus rose, and several infants died. The formulation was withdrawn and the dose dropped back to 1 milligram, but confidence had been shaken: of more than 16,000 infants born in Britain in a single week in 1970, only 20% received vitamin K. This history shows the aftershocks of a single overdose incident can last decades.
— Erin WelshThe 1990s leukemia scare still has not cleared
In the early 1990s two British studies linked intramuscular vitamin K to later leukemia risk, and the reaction was swift and strong: some countries switched to recommending oral dosing and reserved injections for the highest-risk infants, and British injection rates fell from 58% in 1988 to 38% in 1993. But the two studies had small samples and insufficient controls, and a large body of subsequent research and a WHO working group found no association, with IARC also concluding there was no evidence of carcinogenicity. The problem is that bad news travels fast and good news does not, just as with MMR and autism: once doubt is planted, the world never quite recovers.
— Erin WelshRefusal rates doubled, and the 81-fold risk is badly underestimated
US refusal rates nearly doubled from 2017 to 2024, rising from 3% to 5.8%, with some hospitals reporting higher. Infants whose parents refuse have 81 times the risk of vitamin K deficiency bleeding, and that number is badly underestimated because the bleeding itself remains rare and communication is inadequate. Research shows most parents, whether they accept or refuse, know vitamin K is related to bleeding, but do not know that this bleeding can cause severe brain injury and a mortality risk above 20%. The information is present, but it is not being effectively conveyed.
— Erin WelshRefusal reasons fall into three buckets, and birth attendants matter enormously
Refusal reasons fall roughly into three categories: distrust of medicine, pursuit of "natural birth," and preference for alternative medical lifestyles. Some argue that if infants needed more vitamin K, evolution or God would have provided it; some read the recommendation to supplement vitamin K as "you are not fit to be a mother." Research also finds refusers are more likely to be white, college-educated, over 30, and planning a home or birth-center delivery. The birth attendant's stance is critical: in a New Zealand survey, 100% of doctors thought all infants should receive vitamin K, while only 55% of midwives did, and 26% of those would not give it to their own children; in Canada, infants delivered by midwives were 8 times more likely to have vitamin K refused than those delivered by doctors.
— Erin WelshDoctors are seeing newborns bleed to death for the first time
Some parents who lost a child or whose child suffered brain injury because vitamin K was not given are doing something very brave: saying publicly, "I made this decision, this is the consequence, do not do what I did." At the same time, doctors are seeing newborns bleed to death for the first time in their careers, and they are raising the alarm in their communities. Some researchers and doctors are pushing to establish a national US registry of vitamin K refusal and administration, because vitamin K deficiency bleeding is not a notifiable disease and cases are very likely undercounted. In a post-pandemic era when expertise is treated as a dirty word, these preventable injuries and deaths will keep increasing.
— Erin WelshIn their own words · checked verbatim
This may be the hardest part of Olive's story that I will write, the part where I admit that what happened to her was nearly 100% preventable.
Olive's mother1:02
The amount of vitamin K in breast milk really can vary, but on average, it's about 2.5 micrograms per liter of breast milk.
Erin Allman-Updyke21:35
Babies who receive no vitamin K prophylaxis are 81 times more likely to have a late bleed.
Erin Allman-Updyke25:46
since the vitamin does no harm and may do good, it is probably best to give it to all premature infants immediately after birth
Erin Welsh44:27
there was inadequate evidence in humans and experimental animals for the carcinogenicity of vitamin K substances
Erin Welsh48:34
Vitamin K has been swept along with the other medical interventions rejected in this post-pandemic world where expertise has become a bad word.
Erin Welsh55:46
Figures
| Average vitamin K concentration in breast milk | About 2.5 micrograms per liter | 21:35 |
| Daily vitamin K intake of exclusively breastfed infants in the first six months | Less than 1 microgram | 21:35 |
| Share of late vitamin K deficiency bleeding that is intracranial hemorrhage | About 60% | 22:35 |
| Mortality of late vitamin K deficiency bleeding | 50%-60%, about 20% in modern data | 22:35 |
| Relative risk of late bleeding in infants receiving no prophylaxis | 81 times higher | 25:46 |
| US vitamin K refusal rate, 2017 to 2024 | Rose from 3% to 5.8% | 49:35 |
| Vitamin K content of formula relative to breast milk | 10 to 100 times higher | 1:02:56 |
Glossary
- vitamin K deficiency bleeding
- Bleeding in newborns caused by a clotting disorder from vitamin K deficiency, which can occur in early, classic and late periods.
- intramuscular injection
- Injecting a drug into muscle; the standard way vitamin K prophylaxis is given to newborns.
- kernicterus
- Brain damage caused by severe jaundice, which appeared in the 1950s high-dose vitamin K trials.
- menaquinones
- The collective name for vitamin K2, produced by bacteria, including variants such as MK-4 and MK-7.
- phylloquinone
- Vitamin K1, derived from plants, the most common form of vitamin K in medicine and diet.
- GLA proteins
- A class of proteins that require vitamin K-dependent carboxylation to be activated, involved in clotting, bone and blood vessels.
How to listen
Suited to readers following public health, pediatrics and vaccine hesitancy, especially anyone trying to understand the trust machinery behind why a single preventive shot gets refused.
The quarantini cocktail segment at the top and the reference list at the end can be skipped.