A recent post on X drew thousands of views, prompting us to examine its claim that vitamin K injections are harmful to newborn babies. The post alleged that the injections could cause serious side effects, including seizures and damage to vital organs such as the kidneys and liver.

The post included a video from Gubba Homestead, a content creator whose posts often focus on modern homesteading, natural skincare and “non-toxic” lifestyle products. In the video, she claimed that babies are born with low vitamin K levels for a natural reason, that this helps stem cell-rich cord blood (the blood left in the umbilical cord and placenta after birth) reach parts of the baby’s body supposedly affected during labour. She further suggested that hospitals unnecessarily override this process by giving newborns a synthetic vitamin K injection.

To better understand the claim, we first looked into how commonly these injections are given to newborns. Vitamin K injections are a standard part of newborn care, with almost every baby born in a Singapore hospital receiving one shortly after birth. For example, KK Women’s and Children’s Hospital states that the injection is given within the first few hours of life as standard practice for all newborns.

Given how routinely these injections are administered, and the serious harms raised in the post, we took a closer look at whether the claim is credible and how the post’s creator may have arrived at the conclusion that vitamin K injections could be harmful to newborns.

Is Vitamin K important? 

Vitamin K is an essential nutrient that helps blood clot. According to Singapore’s National University Hospital, babies are born with very little vitamin K stored in their bodies. Only small amounts are passed from the mother during pregnancy, and breastfeeding does not provide enough vitamin K to build these stores quickly after birth.

As a result, newborns have only a limited supply of vitamin K at birth, and this can be used up within the first few days of life. This makes them vulnerable to vitamin K deficiency bleeding (VKDB), a rare but potentially fatal condition in which a baby may bleed spontaneously from the umbilical cord site, nose, mouth or even the brain. Hence, vitamin K supplementation is recommended to prevent VKDB.

Vitamin K deficiency is not limited to newborns. Adults can also develop it due to liver or gut diseases, or as a side effect of long-term medication. Vitamin K may also be given to reverse the effects of an overdose of blood-thinning medication.

The claim made in the video that babies are born with low vitamin K levels so that cord blood can travel to parts of the body affected by labour is not supported by medical evidence. While newborns do have low vitamin K levels at birth, there is no evidence that this is an intentional biological design to help cord blood reach damaged tissue, or that vitamin K injections disrupt that process. Cord blood also has extremely low levels of vitamin K, often too low to be detected.

Therefore, it is inaccurate to state that hospitals are “unnecessarily overriding” a natural process. The vitamin K shot is a standard preventive treatment that has been well studied and shown to reliably reduce the risk of serious bleeding in newborns.

Misunderstanding a label?

The dangerous side effects listed in the X post appear to have been drawn from package inserts accompanying vitamin K medication. These documents typically set out possible adverse reactions and other safety information.

In looking into those warnings, one thing that repeatedly came up on social media was vitamin K’s so-called “black box warning”. In the US, vitamin K carries what is more accurately called a boxed warning (a bold, black-bordered notice at the top of a drug’s label or package insert), which is the strongest safety warning required by the US Food and Drug Administration (FDA). Boxed warnings are intended to alert healthcare professionals to serious risks linked to a medicine, so they can weigh its risks and benefits carefully and take steps to reduce the chance of harm. They may also highlight situations in which a medicine should not be used.

An important detail often left out is that the most serious risks highlighted in the boxed warning are associated mainly with intravenous (IV) use of vitamin K, where the medicine is delivered directly into a vein. This is usually in adults with serious liver disease or other complex medical conditions.

By contrast, babies do not receive vitamin K through an IV as part of routine newborn care. It is usually given as a single injection into the thigh muscle which allows the vitamin to be available for use quickly. The most commonly reported side effects are mild, such as irritation at the injection site, while serious side effects in newborns are extremely rare. Overall, vitamin K is considered safe for newborns.

However, social media posts often repeat the term “black box warning” without explaining the context of the warning itself. In doing so, they can make the risks sound more alarming than they are in the setting being discussed.

Given the available evidence from healthcare providers in Singapore and around the world, we rate the claim that vitamin K injections are harmful for newborns as false. This underscores the importance of checking health claims shared online against evidence from trusted medical institutions and qualified healthcare professionals, rather than accepting them at face value.