After the birth of your baby, one of the first decisions you need to make is whether to have a vitamin K injection administered to your baby.
This has been a standard, routine procedure in many countries for over 50 years.
Even so, few people really know a great deal about the injection other than it’s to prevent vitamin K deficiency bleeding in newborns (VKDB).
Some parents question whether the vitamin K injection is necessary, or has side effects.
Let’s look at the vitamin K shot and whether newborns are actually deficient in this important nutrient.
What is vitamin K?
Vitamin K is a fat-soluble vitamin, which means it’s absorbed through the small intestine with the fat we eat, and transported to the liver for storage.
It can also be found in the brain, heart, pancreas, and bones.
There are two types of naturally occurring vitamin K:
- Vitamin K1 (phylloquinone), found in plants, especially leafy green vegetables.
- Vitamin K2 (menaquinone), formed by bacteria living in our intestinal tracts, and found in fermented foods and animal foods.
The body metabolizes and excretes Vitamin K quite quickly, which means very little is found in the bloodstream and body tissues.
We don’t know a lot about vitamin K produced by gut bacteria, but research seems to show it satisfies some of the body’s requirements for vitamin K.
The body recycles vitamin K, through a process called the vitamin K-epoxide cycle. This recycling allows a small amount of vitamin K to be reused many times and explains why oral requirements are so low.
What does vitamin K do?
Vitamin K helps the liver produce proteins needed for clotting blood, which controls bleeding.
We need only a small amount of vitamin K for effective blood clotting.
If vitamin K levels drop, the clotting factors are slow to be activated. This makes it harder for blood to clot and increases the risk of excessive bleeding.
If levels of vitamin K are so low that clotting factors can’t be activated, we can begin to bleed spontaneously.
The specific daily requirement of vitamin K is difficult to determine, because it is not only obtained from dietary sources, but also made within the body, and recycled by the body.
Do we make vitamin K in our body?
It’s very rare for adults to be deficient in vitamin K, unless they have malabsorption disorders or they take medications that interfere with vitamin K metabolism.
As well as making vitamin K within the small intestine, the body obtains vitamin K from dietary sources, including:
- Fermented soy products, especially natto
- Dark green leafy vegetables, such as kale, collards, green leaf lettuce, mustard greens, basil, parsley, romaine lettuce, spinach, Swiss chard, and turnip greens
- Vegetables, such as cabbage, Brussels sprouts, spring onions, cucumbers, broccoli, cauliflower, asparagus, fennel, and leeks
- Dried fruit, such as prunes
- Plant oils, such as olive oil
Why do babies get vitamin K shot?
A vitamin K shot is given to newborns to prevent low levels of vitamin K and the rare condition of vitamin K deficiency bleeding (VKDB).
VKDB happens when babies can’t stop bleeding because their blood doesn’t have enough vitamin K to clot.
The bleeding can happen anywhere, inside or outside of the body. When the bleeding is inside the body, it’s difficult to notice.
Commonly, babies with VKDB will bleed into the intestines or into the brain, which can lead to brain damage and even death.
Infants who don’t receive a vitamin K shot at birth can develop VKDB at any time up to 6 months of age.
Since babies can be affected until they are 6 months old, healthcare providers divide VKDB into three types: early, classical and late, as explained below:
- Early and classical VKDB are more common, occurring in 1 in 60 to 1 in 250 newborns. Babies whose mothers used certain medications during pregnancy have a higher risk for early VKDB.
- Late VKDB is rarer, occurring in 1 in 14,000 to 1 in 25,000 infants.
Research from 30 years ago showed that newborns who don’t have a vitamin K shot are 81 times more likely to develop Late VKDB than those who do.
You can read more about Vitamin K Deficiency Bleeding In Newborns here.
Is the vitamin K shot necessary?
All babies are born with levels of vitamin K that are about 30-60% lower than those of adults.
To date, these lower levels have been considered and treated as a deficiency, rather than a normal occurrence.
In the last few decades, research has progressed. It shows newborns don’t have the same coagulation system as adults, which is used as the benchmark for vitamin K levels.
It’s normal for babies to have low levels of vitamin K. We now know nature is determined to ensure these levels remain low.
Consider these facts:
- There is little transfer of vitamin K1 from the mother to baby via the placenta.
- Babies aren’t born with enough bacteria in their intestines to make vitamin K2.
- Breast milk has low levels of vitamin K, compared with other mammal milk, such as cow’s milk, or fortified infant formula.
This supports the idea that nature certainly didn’t get it wrong. Universally, babies are born with levels of vitamin K that are lower than those of adults, for a reason.
In order for human beings to absorb vitamin K, they need to have a functioning biliary and pancreatic system.
At birth, a newborn’s pancreas and digestive system are still immature and won’t become fully developed until around 6 months of life.
This is why babies need breast milk and don’t take solids until after 6 months of age. It helps the digestive system to mature and provides beneficial bacteria, which can help produce and process the increasing levels of vitamin K.
Vitamin K levels are virtually undetectable in umbilical cord blood. This suggests babies aren’t receiving any vitamin K from their mothers via placental transfer.
This is normal, especially when we consider babies are born with their own inbuilt system to protect against and repair damage and bleeding in their organs, all thanks to umbilical stem cells.
These stem cells can only travel around the body while the blood remains thin, and when the umbilical cord is left intact after birth (delayed cord clamping).
It wasn’t until the late 1980s that cord stem cells were discovered, a few decades after the vitamin K shot had become routine for all newborns.
Does vitamin K cross the placenta?
According to this study, there is a specific vitamin K2 transport system in the human placenta.
A subtype of vitamin K2 (Menaquinone-4 or MK-4) is transferred through the placenta at a higher rate than vitamin K1. This transfer activity increases in the third trimester, before baby is born.
The study points out there’s little vitamin K1 transfer to the fetus. This has been viewed as a poor transfer of vitamin K overall.
The study also suggests the wrong type of vitamin K has been looked at when working out whether vitamin K crosses the placenta.
Is there vitamin K in breast milk?
Vitamin K is naturally present in breast milk but is considered to be too low, in comparison with other mammals’ milk or with fortified formulas.
Vitamin K is found more readily in colostrum and in hindmilk, which is high in fat and comes after the watery foremilk.
Colostrum is the nutrient-rich first milk. It helps your baby’s immune system by colonizing the gut with prebiotics and probiotics, as well as forming a protective barrier against unhelpful bacteria.
Colostrum also contains significantly higher levels of vitamin K than mature milk. Babies who breastfeed soon after birth, and who feed frequently and for as long they want, will obtain more colostrum than babies who don’t.
This is relevant when we consider research into vitamin K levels in breast milk was originally done in the days when babies were often unable to breastfeed for quite some time after birth.
A strict feeding routine was the norm – instigated in hospitals and encouraged at home. This practice possibly interfered with the intake of vitamin K that babies need.
Maternal vitamin K supplementation
Research shows that when women consume vitamin K1 their tissues are able to convert part of it into the vitamin K2 subtype MK-4, which is essential for growing infants.
There also appears to be a way in which the breast concentrates vitamin K2 in mammary glands, ensuring an adequate supply of this nutrient to infants.
Exclusive breastfeeding has long been considered an increased risk factor for vitamin K deficiency bleeding (VKDB).
Until the last 100 years, babies were exclusively breastfed, either by their mothers or wet nurses, and extended breastfeeding (feeding beyond 12 months) was more common than unusual.
Until the Industrial Revolution brought the convenience of packaged food, most people ate simple diets that included plenty of vegetables, animal protein, and fat.
Food wasn’t processed, other than to be preserved, no synthetic chemicals were added, and it was often seasonal and fresh.
Antibiotics were still in the future, and many cultures favored fermented foods – particularly as a form of preserving vegetables for the winter months.
Since the early 20th century, there have been significant changes to our diets, medical practices, pregnancy care, and attitudes to breastfeeding, compared with the previous 100 years, and earlier.
It’s quite likely these changes have affected vitamin K transfer between mothers and babies – during pregnancy, and in the postnatal period.
When should vitamin K be given?
Some parents wish to delay a vitamin K shot for their newborn. Some choose it only if there are complications that could increase the risk of bleeding problems for their baby.
You will need to discuss your choice with your doctor or healthcare provider.
If you choose vitamin K for your newborn, it will be given soon after birth.
You can request a delay until after the first hour, when you’re having skin to skin and getting breastfeeding started.
It’s important the first hour is undisturbed to ensure your baby is able to initiate breastfeeding.
What are the ingredients in the vitamin K shot?
Here are the ingredients in the vitamin K shot:
- Synthetic vitamin K (Phytonadione)
- Polyoxyethylated fatty acid derivative (derived from castor oil)
- Dextrose Monohydrate (glucose)
- Benzyl alcohol
- Hydrochloric acid
It’s certainly a personal decision for parents, as to whether or not their babies have the vitamin K shot at birth.
Do some research before making your decision. Your care provider must respect your informed choice.
How long does the vitamin K shot last?
It’s thought the vitamin K from the injection is temporarily stored in the leg muscle and gradually released into the baby’s system over several months.
By the time your baby is 6 months old, the baby’s own body is making adequate levels.
This kind of delayed release explains why the vitamin K shot protects babies from late VKDB.
Does the vitamin K shot have a black box warning?
The warning on the packaging has instructions about how to give the vitamin K shot to your baby.
It is quite clear the vitamin K shot must not be given intravenously (into the vein). This is because a large dose of vitamin K given rapidly into the vein increases the risk of severe, life-threatening allergic reactions (anaphylaxis).
Most vitamin K is given via an injection or shot into the muscle of the thigh.
Vitamin K can also be administered orally, but this has to be done over several doses and isn’t recommended for sick or premature babies.
Is vitamin K a vaccine?
The vitamin K shot is not a vaccine. Vitamins are essential nutrients that can’t usually be made by the body.
Vaccines work by triggering your body’s immune system, but vitamin K doesn’t trigger the baby’s immune system.
People confuse vitamin K with vaccines because it’s given by injection.
Can vitamin K shot cause jaundice?
Jaundice associated with vitamin K has been observed only in higher-risk babies (such as premature babies) and in doses, 30-60 times higher than the dose given.
Babies with liver disease of the newborn are also considered at higher risk for jaundice if given the vitamin K shot.
It must always be considered whether the risks outweigh the benefits; higher-risk babies don’t have a vitamin K shot.
Be sure to check for these signs of jaundice in your baby:
- Yellow-orange tinge to the skin – it might start on the face and then progress down the tummy and legs
- The whites of the eyes are yellow
- Baby is very sleepy and lethargic
- Baby doesn’t want to feed, or can only latch for short periods
If your baby has these symptoms, contact your doctor or midwife to discuss them. Your baby might require a blood test or medical treatment.
For more information, please read Jaundice In Newborns – The Truth About Jaundice.
Oral vitamin K for newborns
The main concern for care providers who use oral vitamin K is to make sure the baby ingests the dose, rather than spitting it or vomiting it up, and the baby receives all doses on the schedule.
A study from 1997 showed that, although oral vitamin K mostly lowers the risk of vitamin K deficiency bleeding (VKDB), it’s less effective than the vitamin K shot.
Oral vitamin K is also a concern in the rare occurrence of a baby having undiagnosed gallbladder problems, where babies are unable to absorb fat, including fat-soluble vitamins such as vitamin K. It can increase their risk of vitamin k deficiency bleeding (VKDB).
If you use a weekly or daily oral vitamin K regimen, it’s important you make sure your baby has the dose with a feed; taking it on an empty stomach might mean it is not absorbed so well.
Oral vitamin K drops
Studies have shown oral dosing of vitamin K is as effective as a dose given by injection, as long as the correct doses and schedules are followed.
The oral method requires multiple doses. Babies are given 1 mg of vitamin K at birth, followed by a daily low dose from weeks 1 to 13, or they are given three 1 mg doses – at birth, at 1 week, and at 6 weeks.
Alternatives to vitamin K shot
If you plan not to have your baby receive the vitamin K shot, there are a few things to consider.
It’s always better to obtain nutrients from natural sources.
Dietary supplements might not have the levels of vitamin K they claim, and you should check which subtype of vitamin K they include.
More recent research in this area suggests the level of vitamin K in breast milk is sufficient to prevent vitamin K deficiency, despite most health experts maintaining the opposite.
A 2002 study looked at the effects of vitamin K1 supplementation on levels in breast milk.
Mothers were given 0.8, 2.0, or 4.0 mg of Vitamin K1, or a placebo, daily between days 4 and 16 after birth. The researchers found the higher the dose of vitamin K received, the higher the levels found in breast milk.
The study also found that supplementing with vitamin K1 increased the levels of a vitamin K2 subtype called MK-4. This is important because MK-4 is a preferred form of vitamin K for the brain.
MK-4 activates proteins involved in maintaining the structure of brain cell membranes and also manages inflammation and oxidative stress in the brain.
Vitamin K2 is particularly affected by the use of blood thinners, and by gut health.
Another study, from 2004, compared the milk from mothers living in different areas of Japan.
Researchers noted differences in vitamin K concentrations, which were attributed to the differences in the dietary habits of the women. Fermented soybeans (natto) is a particularly high source of vitamin K2.
An earlier study, from 1997, found that 2.5 and 5.0 mg of vitamin K1, when women receive vitamin k daily in the postpartum period, significantly increased the levels of vitamin K1 in breast milk.
The researchers from the study discovered this increase in breast milk vitamin K led to higher concentrations of the vitamin in blood plasma and decreased markers indicating vitamin K deficiency.
This finding is important; it shows vitamin K does reach the infant and decreases the risk of vitamin K deficiency bleeding.
Daily recommendations of vitamin K
The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day.
- The RDA for vitamins can be used as goals for each person.
- How much of each vitamin you need depends on your age and sex.
- Other factors, such as pregnancy, breastfeeding, and illness, might increase the amount you need.
The Food and Nutrition Board at the Institute of Medicine has recommended intakes for individuals.
Adequate Intakes (AIs) for vitamin K are:
- 0 to 6 months: 2.0 micrograms per day (mcg/day)
- 7 to 12 months: 2.5 mcg/day
- 1 to 3 years: 30 mcg/day
- 4 to 8 years: 55 mcg/day
- 9 to 13 years: 60 mcg/day
Adolescents and adults
- Males and females aged 14 to 18: 75 mcg/day (including females who are pregnant and lactating)
- Males and females aged 19 and older: 90 mcg/day for females (including those who are pregnant and lactating) and 120 mcg/day for males
Check with your health care provider before taking supplements while pregnant or breastfeeding, as vitamin K can interfere with certain medications.
Diet to increase vitamin K levels
To increase and maintain vitamin K levels during pregnancy and breastfeeding, try these dietary tips:
- Eat dark leafy greens, for vitamin K1.
- Prepare meals with plant oils that include vitamin K, and consume healthy fats to boost absorption of the fat-soluble vitamin K.
- Include fermented foods in your diet, to boost vitamin K levels.
- Build and maintain your gut bacteria by consuming fermented foods and avoiding antibiotics. Bacteria in the gut can make vitamin K2 and then be absorbed into the bloodstream.
Can parents refuse vitamin K?
As new parents, you will have many decisions to make in your newborn’s first week of life and, in fact, for the most of your child’s life.
You can refuse vitamin K at birth.
As parents, you have the right to decline any medication you feel is not right for you or your baby. The vitamin K shot at birth is no exception.