Newborns naturally have low levels of vitamin K at birth. The danger of low vitamin K levels is the risk of vitamin K deficiency bleeding. This is a rare but severe complication. You can decrease the risk of vitamin K deficiency bleeding by giving your baby a vitamin K shot shortly after birth. Administering vitamin K to newborns is standard in the United States and many other countries. As with any intervention, there are pros and cons to consider. This episode examines the evidence on the efficacy and safety of the vitamin K shot so you can make an informed choice for your baby.

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Standard Procedures

In the United States and many other Western countries, administering the vitamin K shot to newborns is a standard procedure at all hospitals and birth centers. In most cases, just because something is standard procedure doesn’t always mean it is mandatory. As with any intervention, this should come with informed consent, and you should be able to opt in or out. However, some U.S. states like New York, Oregon, and Maine mandate vitamin K. If your state mandates this, you cannot opt-out.

Vitamin K

Vitamin K is a fat-soluble vitamin stored in fat tissue and the liver. The primary function of vitamin K is for blood to clot. The K comes from the German word “koagulation.” There are a few different types of vitamin K. Plants use K1 in photosynthesis, and it is in leafy green vegetables. Vitamin K2 is in fermented foods and animal products, and bacteria in your intestines also produce K2. If you take a vitamin D supplement, it may include K2. Vitamin K helps deliver calcium transported by vitamin D to your bones rather than allowing the calcium to build up in your arteries.

Newborn Vitamin K Deficiency

At birth, babies naturally have low levels of vitamin K. One reason is that the placenta only transfers minimal amounts of vitamin K to your baby. The other reason is that the bacteria that produce vitamin K are not yet present in your baby’s intestines. Once your baby is around six months old and eats solid foods, they have a much lower risk of vitamin K deficiency.

Risk Factors for Vitamin K Deficiency

One risk factor for vitamin K deficiency is exclusive breastfeeding. Babies fed formula tend to have higher levels of Vitamin K because manufacturers fortify the formula with vitamin K. Babies with liver disease are at a higher risk for deficiency. If your baby has diarrhea, celiac disease, or cystic fibrosis, they may have difficulty absorbing vitamins, including vitamin K. If a mother takes some medications, like those used to treat seizures, these drugs can also increase the risk for vitamin K deficiency.

Vitamin K Deficiency Bleeding

The danger of having low vitamin K levels is the risk of vitamin K deficiency bleeding (VKDB). This happens when babies cannot stop bleeding because they do not have enough vitamin K to form a clot. Vitamin K deficiency bleeding can be internal or external. In most cases, there are no warning signs before a life-threatening event. If a baby does develop symptoms of deficiency, they may present as:

  • Bruises, especially on the head or face
  • Bleeding from the nose or umbilical cord
  • Skin becoming paler. In babies with darker skin, their gums may appear pale.
  • The whites of their eyes may appear yellow after three weeks of age
  • The stool may have blood in it or appear dark and sticky. (In the first 24 hours after birth, your baby’s first stools will contain meconium, which is a thick, dark, tar-like poop and is normal.)
  • Vomiting blood
  • Signs of brain bleeding include irritability, seizures, excessive sleepiness, or vomiting.

There are three types of vitamin K deficiency bleeding, and each is classified by when it occurs. Early vitamin K deficiency bleeding occurs within 24 hours after birth. This is most common in babies whose mothers took medications that increase the risk for vitamin K deficiency. Classical vitamin K deficiency bleeding happens within the first week after birth. This presents as bruising or bleeding from the umbilical cord. Early and classical vitamin K deficiency bleeding affects between 1 in 60 to 1 in 250 newborns. Late vitamin K deficiency bleeding occurs within the first six months. 30-60% of infants with late onset have bleeding in the brain, and warning bleeds are rare. Late vitamin K deficiency affects 1 in 14,000 to 1 in 25,000 infants. This happens most commonly with exclusively breastfed babies who do not receive the vitamin K shot.

Circumcision and Vaccines

Of course, no parent expects their baby to have an accident or injury that would cause them to bleed. There are a couple of instances that could contribute to bleeding. This will be if you plan to have your child circumcised or given vaccines. Circumcision usually takes place within a few days after birth and is cited as a common bleeding site for babies who have classical VKDB. In addition, there are some case studies of bleeding at the injection site of a vaccine. Some vaccines, like hep B, are recommended shortly after birth.

Prevention of Vitamin K Deficiency

The good news is you can prevent vitamin K deficiency in your baby with prophylactic administration of vitamin K. Prophylactic means the treatment is given in advance to prevent something. Newborns most commonly receive vitamin K as a shot, but oral vitamin K may also be an option. There is a lot of evidence that giving a newborn vitamin K dramatically reduces the instances of VKDB.

Vitamin K Shot

The best way to prevent VKDB is to administer an injection of vitamin K. Intramuscular injection allows your baby to store the fat-soluble vitamin in the muscle and release it over a period of time. The goal of the shot is to provide vitamin K until your baby is producing enough on their own. This procedure can take place while your baby is on your chest. You can even breastfeed while your baby gets the shot, which may help distract them from it. Breastfeeding releases oxytocin, which may help with any discomfort from the shot.

Recommendations from the American Academy of Pediatrics

The American Academy of Pediatrics is one of many organizations that recommend that all newborns receive a vitamin K shot. The AAP policy statement was most recently reaffirmed in 2022 and states that intramuscular administration of vitamin K for prevention of vitamin K deficiency bleeding (VKDB) has been a standard of care since the American Academy of Pediatrics recommended it in 1961. Despite the success of prevention of VKDB with vitamin K administration, the incidence of VKDB appears to be on the rise. This increase in incidence of VKDB is attributable to parental refusal as well as lowered efficacy of alternate methods of administration. The official recommendation of the AAP is that all newborns receive a vitamin K shot within six hours after birth. As a result, your pediatrician will likely recommend the vitamin K shot for your baby.

Vitamin K Shot Safety

The generic name for the vitamin K shot is phytonadione, the synthetic form of vitamin K. It also includes other ingredients to keep the vitamin K mixed in the liquid or prevent it from being too acidic. There are two versions of the injection: one that is preservative-free and another that contains benzyl alcohol as a preservative. Benzyl alcohol is shown to be safe in the dosages included within the vitamin K shot. The majority of hospitals in the United States use the preservative-free version. If you prefer the preservative-free version, please ask your doctor or midwife about the vitamin K they use.

In the early 90s, it was suggested that there was a link between the vitamin K shot and leukemia. Since then, many studies have been done, concluding there is no link between the shot and leukemia or cancer. The risks and side effects of the vitamin K injection are pain, bruising, or swelling at the injection site. Allergic reactions are extremely rare and usually only with intravenous administration, not the injection given to newborns. Only one case of allergic reaction to the shot has been reported.

Vitamin K Shot Efficacy

The vitamin K shot is very effective at reducing the risk of VKDB. Evidence shows that the risk of a newborn developing vitamin K deficiency bleeding is 1700/100,000 (one out of 59) if vitamin K is not administered. When intramuscular vitamin K is administered, vitamin K deficiency bleeding risk is reduced to 1/100,000. According to the CDC, infants who do not receive a vitamin K shot at birth are 81 times more likely to develop late VKDB than infants who receive a vitamin K shot at birth. You can dig deeper into the research in this Cochrane review or this systematic review.

Oral Vitamin K

Although you can purchase a liquid vitamin K supplement, there is no FDA-approved formulation of oral vitamin K in the United States. If you live in another country, your doctor may give you the option to give your baby vitamin K orally rather than as an injection. If you are considering oral vitamin K, please discuss it with your doctor, midwife, or pediatrician. Your baby may need more than one dose. It is essential to follow instructions from your pediatrician about when to give your baby vitamin K and the exact dosage.

There are fewer studies on oral vitamin K than the shot, but the evidence does show oral administration improves vitamin K levels in the first week of life. There is research showing oral administration effectively raises vitamin K levels, but this research does not include instances of VKDB. The American Academy of Pediatrics acknowledges that oral vitamin K appears to be effective in preventing classic VKDB but notes that there are concerns about its ability to prevent late-onset VKDB, even with a multiple-dose schedule.

Comparing Injection vs. Oral Administration

A Cochrane Review that compared oral and injection noted that neither form of vitamin K had been tested in randomized trials for its effect on late VKDB. Intramuscular vitamin K has trials for classic VKDB, but no trials exist for oral administration.

VKDB is a rare complication, and for research to assess the impact of prophylactic vitamin K on VKDB outcomes, it needs to include a massive number of participants. No randomized trial includes participants who had a shot, oral vitamin K, and a placebo, showing outcomes on VKDB. Since we have plenty of evidence that the administration of vitamin K dramatically reduces the instances of VKDB, it would be irresponsible to carry out a trial and give babies a placebo.

Overall, the shot has more evidence of efficacy. If you oppose the shot, oral vitamin K is evidence-based over no supplementation.

Weighing the Risks and Benefits

One way to weigh the risks and benefits is to compare the risks of the shot to the risks of VKDB. This involves considering whether you will exclusively breastfeed your baby, which puts them at a higher risk of deficiency. If you are taking a medication that affects vitamin K levels, you should consider giving your baby the vitamin K shot. You may also consider whether you plan to circumcise your baby or give them the Hep B vaccine. Although VKDB is rare, there is a risk of death. The vitamin K shot has a long safety record with minimal mild side effects.

Talking to Your Doctor or Midwife

Parenting requires making a lot of decisions that will affect your baby. Thankfully, the doctor or midwife you see for prenatal care is an excellent resource to help you navigate these decisions. If you have any questions about giving your baby vitamin K, please bring them up with your care provider during one of your prenatal appointments. Vitamin K is given to your baby within six hours of your birth. This is not something you want to discuss or be put on the spot to decide right after you have your baby.

Including Vitamin K in Your Birth Plan

The only reason to include vitamin K in your birth plan is to opt out of the procedure. If you want to opt-out, discuss it with your care provider to ensure they support your preference. You must also verify that your state does not mandate vitamin K for newborns. The key to having a successful birth plan is working with your care provider throughout your prenatal care. When done right, your doctor or midwife knows your preferences and supports them without ever having to review the actual birth plan document during your labor.

The Pregnancy Podcast has several resources to help you create your birth plan: 

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