Importance, Safety And Side Effects

The American Academy of Pediatrics (AAP) advises administering a vitamin K shot at birth to newborns. Vitamin K is a vital fat-soluble vitamin crucial in maintaining various physiological functions, including blood clotting. The body stores the vitamin in the liver, brain, heart, pancreas, and bones, but these reserves are limited in newborns. Therefore, they are at an increased risk of vitamin K deficiency bleeding (VKDB), a rare but serious blood disorder that most often affects babies in the first days or weeks of life (1) (2) (3).

Keep reading to learn more about the safety, significance, and possible side effects of the vitamin K shot for infants.

Why Is Vitamin K Necessary For Newborn Babies?

Newborns are at risk of developing a bleeding disorder called vitamin K deficiency bleeding (VKDB) due to their low stores of vitamin K at birth. This condition can lead to excessive bleeding or hemorrhage in the intestines and brain, which can cause brain damage and may even be life-threatening. Thus, babies must receive a vitamin k shot at birth to prevent VKDB. Infants who do not receive the shot may be affected by the condition up to six months of age (2) (4).

Vitamin K deficiency bleeding is generally grouped into three categories (5) (6).

• Immediate-onset: It is very rare and manifests within the first 48 hours after birth. It is usually a result of some medications taken by mothers during pregnancy.
• Early-onset (formerly called classic-onset): It is also rare but most common among the three. It occurs between one to 14 days after birth and is mostly seen in breastfed infants who did not receive a vitamin K shot at birth.
• Late-onset VKDB: It may occur between two weeks and six months after birth. Infants who have not received vitamin K prophylaxis are more susceptible.

Why Do Infants Have Low Levels Of Vitamin K?

Infants have low levels of vitamin K at birth for a few reasons (1) (7).

• Babies do not develop sufficient vitamin K reserves in their bodies while in the womb as the vitamin does not move freely across the placenta from the mother to the fetus.
• Newborns do not have sufficient stores of vitamin K in their livers.
• The adult gut contains certain bacteria that help synthesize vitamin K in the large intestine. However, these bacteria are absent in neonates.
• Breast milk does not supply much vitamin K to the infant.
• Vitamin K deficiency may occur in babies born to mothers taking certain medications during pregnancy. These medications include anti-tubercularⁱXDrugs used to treat tuberculosis (TB) drugs (isoniazid, rifampicin), antiseizureⁱXDrugs/techniques used to treat epilepsy (phenytoin, barbiturates, and carbamazepine), antibiotics (cephalosporins), or vitamin K antagonists (warfarin).

Can All Newborns Have Vitamin K Shots?

The Centers for Disease Control and Prevention, USA (CDC) recommends that all babies receive a vitamin K shot immediately after birth. It is because all newborns have low vitamin K levels and are at risk of bleeding (2). However, premature babies may require a lower dose that will be decided by the doctor (8).

How Is Vitamin K Given To Babies?

A one-time shot of one milligram of vitamin K is usually given after the first hour of birth. The vitamin K shot is given intramuscularlyⁱXA method of administering a drug/vaccine into the muscle tissue (IM) in your baby’s thigh within six hours of birth (9). The infant should be in skin-to-skin contact with the mother, and breastfeeding should be started in the first hour (10). The shot may be delayed up to six hours to encourage immediate bonding and contact between the newborn and the mother (11).

Oral vitamin K drops are also available for babies. However, drops are not absorbed efficiently through the intestines, and a baby requires three doses. Therefore, the first dose is given at birth, followed by the second at three to five days, and the third at four weeks after birth. Additionally, oral drops are not suitable for babies if they are premature, taking antibiotics for diarrhea, or are born to mothers taking certain medications during pregnancy. Therefore the CDC recommends the injection over oral drops (8) (11).

Are Vitamin K Shots Safe?

Yes, the vitamin K shot is safe. The baby’s liver stores the vitamin K from the injection, slowly releasing it over months. It maintains the body’s required amount of vitamin K until the baby starts eating solids and obtains the vitamin from food (9).

Besides vitamin K1 (Phytonadione), the other ingredients in the shot are also considered safe. They are (4) (13):

• Polyoxyethylated fatty acid derivative: It is used as a solvent and emulsifierⁱXA substance that helps mix two or more immiscible liquids to keep vitamin K in a dissolved form (as vitamin K is a fat-soluble vitamin).
• Dextrose: It is a simple sugar that is considered safe for newborns.
• Benzyl alcohol: It acts as a preservative and is used in minute quantities to prevent bacterial contamination in the shot.
• Hydrochloride: It may be present in a small amount to adjust the pH of the solution.

Note: You may find reports of toxicity for benzyl alcohol, but the amount required to cause such side effects is about 100 times higher (given daily) than the amount found in the shot.

Are There Any Side Effects Of Giving Vitamin K To The Baby?

The side effect of the vitamin K injection is similar to that of any other shot and may include the following:

• Pain, bruising, or swelling at the injection site
• Skin scarring (may occur in a few cases)
• Allergic reactions (very rare)

You may hold your baby while the shot is being administered or breastfeed them during or immediately after the shot to reduce their discomfort (4).

Where To Get Vitamin K Shot?

Your doctor or midwife will explain the requirement of vitamin K and its mode of administration during your prenatal visits. Then, based on your preference, your baby will get the vitamin soon after birth. If home birth is planned, discuss vitamin K prophylaxisⁱXThe process of preventing a particular disease with your midwife.

If you have opted for oral vitamin K administration, your baby will get the first dose at birth. Then, the second at the time of the newborn screening test (you may also get it from your local healthcare provider), and the third at the hospital, through your local doctor, or a healthcare worker. Ensure to follow the recommended schedule to protect your baby from VKDB (8).

When Is A Baby At A Higher Risk Of Developing VKDB?

Preterm babies, newborns with birth trauma, those requiring surgery, and babies born to mothers who have taken medications during pregnancy that interfere with vitamin K metabolism are at a higher risk of developing vitamin K deficiency and related bleeding (10).

What Are The Possible Symptoms Of Vitamin K Deficiency?

Vitamin K deficiency can cause bleeding, which can occur in several body areas, including (7):

• At the site of circumcision
• In the belly button area
• With stools due to gastrointestinal bleeding
• In the lining of the nose and mouth
• In places where there has been a needle insertion

Some other symptoms of vitamin K deficiency in newborns may include:

• Blood in the baby’s urine
• Appearance of bruises on the skin
• Seizures (due to bleeding inside the skull)

When To Consult A Doctor?

Consult your healthcare provider if your baby has unexplained bleeding, seizures, or abnormal behavior (5).

References:

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Dr. Joyani Das did her post-graduation from Birla Institute of Technology, Mesra and PhD in Pharmacology. Previously, she worked as an associate professor, faculty of Pharmacology, for two years. With her research background in preclinical studies and a zeal for scientific writing, she joined MomJunction as a health writer. Her research work was published in international journals and publications, such…
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