Vitamin K Shot Refusals Have Doubled, and New Studies Link Them to More Infant Bleeding: What Parents Should Know

 In 2017, about 3 out of every 100 newborns in the United States left the hospital without a vitamin K shot. By 2025, it was nearly 7 out of 100.

Two new studies published Thursday in JAMA and JAMA Pediatrics now connect that trend to something more worrying: a sharp rise in life-threatening bleeding among infants.

What the studies found

The JAMA study looked at more than 5.2 million infants using electronic health records. It found that the share of newborns who did not receive the shot rose from 3.1% in 2017 to 6.8% in 2025, more than doubling. Between 2024 and 2025 alone it climbed from 5.6% to 6.8%, ABC News reported.

Babies who did not get the shot had a 47% higher risk of bleeding in their first six months than babies who did, and more than double the risk of bleeding inside the skull. Bloomberg reported that they were also more than twice as likely to die during birth hospitalizations that involved bleeding. The researchers calculated that for every 114 newborns who skip the shot, one additional bleeding event would occur.

The second study, in JAMA Pediatrics by Steven Woolf of Virginia Commonwealth University, found that the share of newborns receiving the shot fell from 97.7% to 95% over the study period, while the rate of vitamin K deficiency bleeding nearly quadrupled and appeared to be accelerating.

The studies come with caveats. Bleeding rates rose in both groups, those who got the shot and those who did not, though faster among those who did not. The authors said some of the overall rise could reflect better detection or sicker mother-infant pairs. The research also does not show why parents are declining the shot. The CDC does not track refusals or bleeding, which is why the studies matter.

Why newborns need vitamin K

Vitamin K helps the blood clot. Babies are born with very low levels of it, because it does not cross easily from mother to baby during pregnancy and breast milk contains very little. Their intestines also do not yet have the bacteria that produce it.

That leaves a window in which a baby can develop vitamin K deficiency bleeding, or VKDB. The bleeding can happen in the brain, in the intestines, under the skin or from the umbilical stump. The most dangerous form, late-onset VKDB, can occur from about two weeks to six months after birth. Hospital system UPMC, citing the medical literature, says 30% to 60% of affected babies bleed into the brain. Babies can look perfectly healthy until it happens, and there is often no warning sign.

What the shot does

The American Academy of Pediatrics has recommended a single vitamin K injection for all newborns since 1961. It is given in the thigh soon after birth. Part of the dose works immediately, and the rest is stored in the liver and released slowly over months.

According to the CDC, babies who do not get the shot are about 81 times more likely to develop late VKDB. An analysis cited by Pharmacy Times says the injection reduces the risk of late VKDB by more than 95%. Side effects are rare, and when they occur they are usually swelling or redness at the injection site, though serious allergic reactions are extremely rare.

It is not a vaccine. It is a vitamin supplement. Doctors told NBC News that parents often lump it in with vaccines.

Why some parents refuse

Parents who decline cite worries about pain, the ingredients, whether it is necessary, and a wish for fewer medical interventions at birth, according to the studies and a 2022 AAP policy statement. Some point to a small 1990 study that suggested a link between vitamin K and childhood cancer. The CDC and others say more than a dozen large studies since have found no connection.

Doctors say the trend is visible at the bedside. One physician told ABC News that on a single day, five of ten babies on the unit left the hospital without it. Researchers note the rise comes during a broader period of skepticism toward public health, though the studies do not point to a cause.

What about oral vitamin K?

Some parents ask about drops instead of a shot. Doctors say that oral vitamin K is not absorbed as reliably and does not protect as well against late bleeding, especially in the brain. The AAP does not support an oral-only approach, and the U.S. has no oral product approved for routine newborn use.

What parents can do

Hospitals must get consent because vitamin K is a medication, so parents have the right to decline. Doctors advise talking to a pediatrician or a midwife during pregnancy, before delivery, so that questions can be answered ahead of time. The AAP and CDC both have guidance for families.

Frequently asked questions

Is the vitamin K shot a vaccine?

No. It is a vitamin given to help blood clot.

Does the vitamin K shot cause cancer?

No. A small 1990s study suggested a link, but larger studies since then have found none, according to the CDC and hospital systems.

When is it given?

Shortly after birth, as a single injection in the baby's thigh.

Can vitamin K be given by mouth instead?

Not as an equal substitute, according to the AAP. Oral doses are less effective, particularly against late bleeding.

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This article is for information only and is not medical advice. Talk to your health care provider about your baby's care. Sources: JAMA, JAMA Pediatrics, Reuters, ABC News, Bloomberg, NBC News, Contemporary Pediatrics, Pharmacy Times, UPMC, CDC and American Academy of Pediatrics guidance, November 5, 2026.