At birth, babies naturally have low levels of vitamin K. The danger in having low levels of vitamin K is the risk of vitamin K deficiency bleeding. This is a rare but serious complication. You can decrease the risk for vitamin k deficiency bleeding with the vitamin K shot. Administering the vitamin K shot to newborns is standard procedure in the United States and many other countries. As with any intervention, there are pros and cons to consider. This article 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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In the United States and many other western countries, administering the vitamin, K shot to newborns is 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 opt-out. However, in some U.S. states, vitamin K is mandatory, and you do not have the option to opt out. Regardless of the laws in your state, this episode will break down the evidence, pros, and cons, so you are informed about vitamin K.
Vitamin K is a fat-soluble vitamin stored in fat tissue and the liver. The main functions of vitamin K are blood coagulation and the health of bones.
The primary function of vitamin K is for blood to clotting. 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 the 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. 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 is eating solid foods, they are at 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 formula with vitamin K. Babies who have 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 in having low levels of vitamin K is the risk of vitamin K deficiency bleeding. This happens when babies cannot stop bleeding because they do not have enough vitamin K to form a clot. There are three types of vitamin K deficiency bleeding (VKDB), 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. This happens most commonly with babies who are exclusively breastfed and do not receive the vitamin K shot. Late vitamin K deficiency affects between 1 in 14,000 to 1 in 25,000 infants.
Vitamin K deficiency bleeding can be internal or external. In the majority of 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
- Stool may have blood in it or appears 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
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. Some vaccines, like hep B, are recommended shortly after birth. Without supplementation, the first few days are when your baby’s vitamin K levels are at their lowest. Circumcision is cited as a common bleeding site for babies who have classical VKDB. There are some case studies of bleeding at the injection site of a vaccine.
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
Babies receive the vitamin K shot within six hours after birth. This procedure can take place while your baby is on your chest. You can even be breastfeeding when your baby gets the shot, which may help distract them from it. Oxytocin is released when your baby nurses, and this may help with any discomfort from the shot. 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.
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 do receive a vitamin K shot at birth. This stat originates from a study done decades ago. Once something is scientifically proven, there is little incentive to perform new research on it. A couple of reviews do a good job of summarizing the research and touching on some studies comparing intramuscular injection and oral administration. You can dig more into the research in this Cochrane review or this systematic review published in 2016.
Vitamin K Shot Safety
There are two types of the vitamin K shot, which contain phytonadione, the synthetic form of vitamin K. Both types contain other ingredients needed to make it safe for injection, like an additive to keep the vitamin K mixed in the liquid or keep it from being too acidic. The main difference is one type has a preservative, and the other is preservative-free. The preservative used is benzyl alcohol, and this is proven 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. You can always ask your doctor or midwife about the vitamin K they use if you have a preference.
Years ago, back 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 only one case of this has been reported.
Vitamin K Shot Efficacy
The vitamin K shot is very effective at reducing the risk of VKDB. Evidence shows the risk that a newborn will develop vitamin K deficiency bleeding is 1700/100,000 (one out of 59) if vitamin K is not administered. When intramuscular vitamin K is administered, the risk of vitamin K deficiency bleeding is reduced to 1/100,000.
Oral Vitamin K
You may have the option to give your baby vitamin K orally rather than as an injection. There is less research on oral vitamin K, but the evidence does show oral administration improves vitamin K levels in the first week of life. Please discuss it with your doctor, midwife, or pediatrician if you are considering oral vitamin K. 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 is research showing oral administration effectively raises vitamin K levels, but this research does not include instances of bleeding.
Comparing the 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 outcome needs to include a massive number of participants. There is no randomized trial including 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 are opposed to the shot, oral vitamin K is evidence-based over no vitamin K supplementation.
American Academy of Pediatrics
Weighing the Risks and Benefits of the Vitamin K Shot
One way to weigh the risks and benefits is to compare the risks of the shot to the risks of VKDB. This would involve considering whether you will exclusively breastfeed your baby, putting them at a higher risk of deficiency. If you are taking a medication that affects vitamin K levels, it would be essential to consider. You may also consider whether you plan to have your baby circumcised. 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, this is something you should discuss with your care provider in advance to make sure they are supportive of your preference. 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.
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