Vitamin K in Newborns

breastfeeding fourth trimester newborn newborn development newborn nutrition vitamin k Jan 08, 2024

On today's concise episode, Drs. Alicia Power and Sarah Lea discuss why newborns are given Vitamin K right after birth, what Vitamin K does in the body, the types of Vitamin K, the causes, effects and treatment of Vitamin K Deficiency Bleeding (VKDB), and how to address parent's potential concerns around administering Vitamin K at birth.


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[00:00:50] Dr. Alicia Power: So what's the deal with vitamin K shot for newborns after birth? Do they really need it? Let's take a deep dive into this particular intervention. What is vitamin K and what does it do in the [00:01:00] body?

[00:01:00] Dr. Sarah Lea: So vitamin K is a fat soluble vitamin that's needed for blood clotting. We cannot make vitamin K ourselves and we don't store it very well in our bodies. We get vitamin K1, also known as phylloquinone, from leafy green vegetables. We also get vitamin K2, which is menaquinone, from bacteria that live in our intestinal tracks. Vitamin K1 from plants makes up about 90% of our overall vitamin K levels. Vitamin K2 from bacteria, it makes up about only 10% of our overall vitamin K intake. Foods that are rich in vitamin K1 include leafy green vegetables like spinach, kale. I'm a said spell.

[00:01:41] Dr. Alicia Power: It's a new it's the new hybrid,

[00:01:44] Dr. Sarah Lea: spinach, kale, swiss chard, and collards. Broccoli cabbage, cauliflower, turnips, brussel sprouts. It sounds like Thanksgiving dinner. Avocado, banana, kiwi and soybean oil.

[00:01:56] Dr. Alicia Power: Those aren't necessarily traditional. Banana and [00:02:00] kiwi might be for dessert, right? So vitamin K is necessary for our bodies to activate certain molecules that help our blood clot. The blood clotting factors are there in normal numbers at birth, but not activated fully due to the low levels of vitamin K. So if we don't have enough vitamin K, then we can't activate these molecules and therefore we can't clot our blood. So vitamin K deficiency makes our blood less able to clot. For the most part, our bodies can continue to clot appropriately with low vitamin K levels. However, as those levels get lower and lower, we can suddenly reach a point where our bodies can no longer clot and we start to bleed spontaneously or for no reason. The level that you have to get down to for bleeding to start varies from person to person. So there's no kind of real way that we can predict it.

[00:02:46] Dr. Sarah Lea: So what can happen if a baby does not have enough vitamin K. This is where the concern comes in from the medical provider perspective, a baby who does not have enough vitamin K can start to bleed spontaneously [00:03:00] and suddenly without any warning, and this is known as vitamin K deficiency bleeding and the vitamin K deficiency bleeding can be for two major reasons. The one is a term we call idiopathic meaning. An unknown reason other than knowing that we have low vitamin K levels. So almost all of these can happen in babies who are exclusively breastfed because breastmilk unlike formula is not a good source of vitamin K. The secondary VKDB Vitamin K Deficiency Bleeding means that the baby typically has an underlying issue such as gallbladder disease, cystic fibrosis, or medication side effects. Most babies who have secondary VKDB, vitamin K deficiency bleeding are also exclusively breastfed.

[00:03:41] Dr. Alicia Power: So vitamin K deficiency bleeding can show up as one of three different patterns. They're called early, classical, and late. So early vitamin K deficiency bleeding happens in the first 24 hours of life. It's usually seen in babies, born to people who took a medicines that interfere with [00:04:00] vitamin K. The medications that cause these are rarely used in pregnancy and probably the most important group of medications to know about are those that are anti-seizure medications. So this bleeding usually happens in the skin brain or the abdomen. Classical vitamin K deficiency bleeding happens in days two to seven of life. Usually days two to three. This is when vitamin K levels are at their lowest common leading sites include the gastrointestinal system or the bowels umbilical cord site, skin nose. And if babies had a circumcision at the circumcision site. The official cause of classical VK, DB is listed as quote unquote, unknown, but breastfeeding and poor feeding are major risk factors. Late VKDB. Her vitamin K deficiency bleeding happens after the first week of life, usually during weeks three to eight, but can happen anytime in the first six months. The bleeding usually happens in the brain skin and bowels. Bleeding in the brain is often the first sign of late VKDB. And this [00:05:00] happens exclusively in breastfed infants, who did not receive a vitamin K shot. Some infants may be at a higher risk if they have undetected, gallbladder disease, cystic fibrosis, chronic diarrhea, antibiotic use. But usually if you've received the vitamin K shot, this still doesn't occur.

[00:05:15] Dr. Sarah Lea: So how common is vitamin K deficiency bleeding or, particularly late vitamin K deficiency bleeding. So late bleeding, which occurs after the first week of life is understandably the most dangerous kind of vitamin K deficiency bleeding. And we know that when infants do not receive any vitamin K at birth studies that are based in Europe, show that anywhere from 4.4 to 7.2 infant out of 100,000 will develop late vitamin K deficiency bleeding. So the number may seem small in a pool of a hundred thousand infants. But what I always say to my patients as an epidemiologist, is that statistics are great when you're talking at a population level, but when you're in that 4.4 to 7.2 range of infants, the statistics don't mean anything.

[00:05:57] So just take that in mind as we go through these [00:06:00] numbers. Using vitamin K supplementation after birth decreases this number, but the amount depends on how it's given. So there are a few different ways, but the most effective way is through a vitamin K shot at birth. The next most effective route is giving two milligrams of oral vitamin K at least three doses from birth to four weeks of age. And these regimens decrease the rates from 4.4 to 7.2 infants per 100,000 to zero to one infants per 100,000. So that's a huge decrease in risk. The vitamin K shot that we give in our healthcare setting is given in the muscle. And this deposit is slowly released over the subsequent weeks to assure that baby has adequate amounts of vitamin K.

[00:06:43] Dr. Alicia Power: So why is this so important? What are the potential consequences of late vitamin K deficiency bleeding? And again, Sarah just talked about this. It's rare, but the consequences can be catastrophic. More than half of the infants who develop this late bleeding will have bleeding in the brain. [00:07:00] The death rate for late vitamin K deficiency bleeding is approximately one in five or 20%. And of those infants who survive about 40% of those have long-term brain damage.

[00:07:11] Dr. Sarah Lea: So what about classical vitamin K deficiency bleeding? So that's up bleeding that sort of happens in the first week of life. Is that dangerous? And so classical vitamin K deficiency bleeding is more common than late vitamin K deficiency bleeding in classical bleeding is usually mild. And involved typically bleeding of the umbilical cord site or at the circumcision site, if the infant underwent circumcision. However, it's important to know that even though the sites may not be as catastrophic as a bleed in the brain, that blood loss can actually be really significant. Fortunately the mortality rate or the rate of infant loss associated with vitamin K deficiency bleeding is generally low in developed countries, if that bleeding is picked up early.

[00:07:53] Dr. Alicia Power: So what is the treatment for vitamin K deficiency bleeding? So the main treatment is to give the infant vitamin [00:08:00] K. So, when an infant comes in with bleeding, they receive a shot of vitamin K1, and this will usually slow or stop the bleeding within 20 to 30 minutes. However, if bleeding happens in the brain, the infant may already have brain damage at the time the shot is given. So that's why that classic is usually less dangerous, because if it's bleeding from the umbilical cord or the circumcision site, that's really easy to see. And so people will, will get help sooner. Versus if babies having bleeding in the brain, the signs aren't always as typical or as obvious to the parents to get help quickly.

[00:08:34] Dr. Sarah Lea: So we have mentioned a couple times that this bleeding, the vitamin K deficiency bleeding usually occurs in breastfed babies. And you might be wondering why is that? So there are generally two main reasons why babies do not have enough vitamin K in their system. First, as we mentioned before, babies are born with very limited amounts of vitamin K. Their levels are lowest at days two to three, and don't really reach adult levels until about six months of age. [00:09:00] And the levels are low because one very little vitamin K one transfers from the mother to the baby, through the placenta. And then two is that babies don't have enough bacteria in their intestines in those first few weeks to months to make vitamin K2.

[00:09:15] The second part of this is that breast milk has really tiny amounts of vitamin K. Levels in breast milk and in colostrum similar. So virtually all babies with late vitamin K deficiency, bleeding are exclusively breastfed. Now, when studies looked closely at infants who develop late VKDB, they found that mothers of these babies had normal levels of vitamin K and their milk supply. So it's thought that maybe some of these babies had a problem with absorbing the vitamin K from their mother's milk.

[00:09:41] Dr. Alicia Power: So why are formula fed babies protected from vitamin K deficiency bleeding? There are virtually no reports of this occurring in infants who are formula fed. And this is because in contrast to breast milk formula has a relatively high level of vitamin K1. On average, babies who are formula fed received nearly 100 times more vitamin K [00:10:00] than babies who are breastfed.

[00:10:02] Dr. Sarah Lea: You know, one of the biggest concerns parents have is what might happen if I give my baby this vitamin K shot. Are there any side effects and the most important thing to know is that side effects from vitamin K injection given at birth are incredibly rare. And if they're seen, they end up being case reports due to how rare they are. That means that they're so uncommon that when it happens, people write it up and put it in the medical literature. So any injection that we get can lead to site irritation and redness. Now this is actually really rare and almost never leads to any intervention required. Injections also cause pain, which can be minimized by nursing the baby during and after the shot. And now you might hear people out there saying that the vitamin K shot can increase the risk of jaundice, but this is old news. This happened in the fifties when the formulation was very different and due to this issue, manufacturers change the formulation and it has not been an issue since. If anyone is saying this, they are using data and literature that is 75 years old. [00:11:00]

[00:11:00] Dr. Alicia Power: So why do we use the vitamin K shot instead of the oral formulation? And there's a few reasons for that. So the vitamin K injection is given as a shot in the muscle, as we said before. And it's the preferred method because one, the shot is absorbed more easily than the oral version. Number two, the shot has a delayed release. So that kind of delayed release overtime protects against both the classical forms and the late forms of vitamin K deficiency bleeding. When the shot is used, specifically, the chance of late vitamin K deficiency bleeding is near zero. The three dose oral version. It doesn't lower the rate of bleeding quite as much as the shot, but it's also very good. However, it's dependent on us remembering to give it. And anyone who has had a newborn can attest the challenge of remembering to just brush your teeth, let alone a weekly oral medication. In some countries, there is a robust public health system in which nurses go and visit regularly. And so they're responsible for bringing the oral vitamin K and administering it. [00:12:00] And so it's a much more robust system to remember those medications. Unfortunately, in many of the places that we live, our communities, can't do this.

[00:12:09] Dr. Sarah Lea: So we know that there's some myths out there on the good old fashioned, worldwide web. And so we thought we would tackle them just with kind of the same advice that we would give anyone in our office because these questions do come up. So the first one is, but aren't low vitamin K levels. Natural. And I find the term natural interesting. And I will not get up on a soap box here, but I think what I would say is that, yes and, infant injury, mortality and loss is also natural and it's something that our medical and healthcare system can now help mitigate. So if we, if we want to take the potential risk of having a baby who has a bleed in their brain, considering that's one of the natural outcomes of low vitamin K levels. Then yes, it's natural. But if we want to take advantage of some of the medical interventions and huge advances we've made and keeping newborns alive and reducing [00:13:00] newborn morbidity and mortality, then I would say, why not?

[00:13:02] Dr. Alicia Power: Exactly? Another question that we often see is I had a trauma free birth. My baby shouldn't be at risk, but if you think of any birth. That baby is being squished. Particularly their head is being squished through a canal that is smaller than their head circumference. And our baby's skull is actually made up of multiple different segments that can cross over each other to allow that baby's head to get through that smaller diameter pelvis. And so there is always microtraumas that are happening. But oftentimes they don't lead to any negative consequences. Sometimes they do. So no birth is quote unquote trauma free just by the nature of the birth I think we can just keep that in mind when we're talking about those things.

[00:13:47] Dr. Sarah Lea: Yeah and I think one thing it's interesting my husband is a physician, and he always says what problem are we trying to solve and so keep that in mind when you're considering not giving your infant the vitamin k shot.[00:14:00] What is it that you're worried about, what problem it is is it that you're trying to solve, and take that into consideration. And have that conversation with your care provider if you're worried because really it's ultimately about informed choice but making sure that you have appropriate evidence and information and that you make the best choice for you and your infant.

[00:14:19] Dr. Alicia Power: Yeah so that is it vitamin k deficiency bleeding, VKDB And why we give the vitamin k shot why we recommend giving the vitamin k shot to all newborns immediately. Or within a few hours after birth.

[00:14:33] Dr. Sarah Lea: Thanks for listening!


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