There has been speculation amongst some people that the Vitamin K shot is unnecessary and simply one of those painful procedures that is done without really considering the need. So I thought I’d do some research and share with you what I could find on the shot to help you make your educated decision.
Types of Vitamin K Deficiency Bleeding (VKDB)
The type of bleeding the Vitamin K shot is supposed to help with comes in three different forms: early (on the first day of life), classic (between the 2nd and 7th day of life), and late (between one week and six months). The early form is very rare and tends to only be apparent in babies whose mothers have certain conditions leading to the use of medication which affects their vitamin K levels. Classic is more common and seems to occur in between 400 and 1700 per 100,000 births (so while not “common”, it certain is a large enough number to warrant concern). Finally, late VKDB is rare and is almost exclusive to breastfed babies and is symptomatic of a liver disease or malabsorption syndrome.
The Shot versus the Oral Dose
We have a problem with needles (as someone with a huge distaste for needles, I shall add, “rightfully so”), and the idea of jabbing a newborn seems barbaric. However, in the case of Vitamin K, it was found that the oral dose was simply not as effective as the intramuscular (i.e., needle) dose. Specifically, although the two seem to offer comparable protection right after birth, late vitamin K deficiency bleeding is actually a greater cause of concern and seems to be better protected by the intramuscular shot. In data from Australia, the rate of late VKDB in children with no Vitamin K shot or oral dose was 34.1/100,000. In children with the oral dose, it ranged from 4.1 to 20/100,000 depending on the number of doses received (up to 3). In children with the intramuscular shot, it was 0.2/100,000. [Of note, if you opt for the oral dose and your child vomits or regurgitates in the first hour after taking the dose, you need to repeat the dose.]
What About the Possible Link to Childhood Cancer?
Some people express concern over the Vitamin K shot because of reports of an association with certain childhood cancers. This stemmed from two studies which found the intramuscular shot was a risk factor for childhood cancer in the UK. Notably, this finding held only for the intramuscular shot and not the oral dose of Vitamin K. However, other large cohort studies in countries such as Denmark, Sweden, the United States, and Germany have failed to find such an association. Therefore it seems that the original findings may have been due to other circumstances or simply served to be a Type 1 error (i.e., when something presents as significant when in reality it is not).
What are the Risks of Not Receiving Vitamin K Prophylaxis?
The primary role of Vitamin K is to allow blood to clot. Without it, infants (and adults) can suffer various haemorrhage-related disorders (but these are very rare). We know that Vitamin K stores increase rapidly over the first week of life and most newborns will have sufficient stores by day 8 (this is most likely the reason for the Jewish bris taking place on the 8th day after birth). Insufficient stores at any time frame increases the risk of various haemorrhagic disorders, but the risks depend on the type and time of VKDB. Children with early and late onset VKDB run a much greater risk of presenting with severe complications (including death) due to higher risk of intracranial or intra-abdominal haemorrhage. Those infants who have classic VKDB (associated with delayed or insufficient feeding and presents in the first week of life) often have mild symptoms including bruising and bleeding from the umbilical site (or any puncture sites from any other shots); however, they can also present with severe blood loss (e.g., from circumcision) and intracranial haemorrhage.
What are the Risk Factors for VKDB?
For early-onset VKDB, we know the main cause is mom being on medications that inhibit vitamin K absorption. In these cases, mom needs to be in contact with a care provider and can be given supplements prior to birth in order to help her newborn not face haemorrhagic diseases. For classic VKDB, being small for gestational age is a risk factor, but the majority of cases are normal term, weight, birth infants. However, birth trauma can be a factor that requires Vitamin K shots and risks of problems from VKDB may be greater if the cord is clamped early due to the lower blood volume the child has. Late VKDB is associated with exclusive breastfeeding and infants with cholestasis or malabsorption syndroms. These disorders are difficult to diagnose, but not impossible (speak to your doctor if you’re concerned and you will most likely want to get your child regularly tested if you did not receive a vitamin K prophylaxis and are exclusively breastfeeding).
Why are Breastfed Babies at Particular Risk?
Vitamin K stores are low at birth to begin with, so all babies start off with low stores (this raises the question of why they are so low – evolutionarily it may be that the risk is so low it just isn’t factoring out or for other, unknown reasons). Formula adds vitamin K to their product, giving infants a direct source. Mothers who breastfeed, however, do pass on vitamin K to their babies, but there are very low doses in breastmilk. Though low, these doses are actually enough to sustain babies’ needs, so long as the infant is feeding regularly. Thus, the relationship to breastfeeding (for classical VKDB) is linked with delayed or inadequate feeding. Similarly, late VKDB is linked to breastfeeding again due to the low levels and the preexisting conditions which put a baby at risk (including malabsorption, thus the low levels are not providing enough). Therefore, the problem is not breastfeeding per se, but that there are medical conditions which affect babies and for which medical interventions save lives whereas the normal course of events (namely, breastfeeding and no vitamin K prophylaxis) would lead to deleterious outcomes. Notably though, formula is NOT recommended just for this. The risks associated with not breastfeeding are documented here.
What Should I Do?
Well, it is up to you to take the data and decide what is best for your family. There don’t seem to be drawbacks to the vitamin K prophylaxis (whether oral or intramuscular) despite some people still claiming the link to cancer. One exception to this is if you have clotting disorders in your family or family history; in this case, the vitamin K shot may actually result in severe complications for your baby. If you are unsure, talk to your care provider about your history and your concerns.
For those who don’t like the idea of giving a shot, the oral dose may be best; just remember to get all 3 doses to reduce the risk of late VKDB, especially if exclusively breastfeeding. Notably if your child needs to undergo any medical procedure early in life, you may have to get the prophylaxis to protect your child as it may be hospital policy (again, unless you have a history of clotting disorders in your family), though you will have to talk to your hospital about it. Some people don’t like the idea of the other components in the shot and that’s why they opt out. You should review what type of shot your country offers and what the ingredients are if this is a concern for you as there are ones with no preservatives, but what is available for you can only be searched by you. The risk of VKDB is very low, but the consequences are very dire, and this is where you must weigh your options based on your history, your beliefs, and the evidence. Like all decisions, this one is yours to make as you have to live with the choice and hopefully the information herein can help you in that decision-making process.
[My only recommendation is that if you choose not to have the Vitamin K shot, please do get your child tested for any late-term deficiencies. The risk of death is high and if symptomatic, it may be too late. You have every right not to have the shot, but you should do what you can to make sure your child doesn’t suffer long-term.]
 Vitamin K Prophylaxsis in the Newborn. A Consensus Statement. http://www.medsafe.govt.nz/profs/puarticles/vitk.htm
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