Vitamin K Deficiency Bleeding: Newborns, Adults, Medicines and Malabsorption

Urgent first

In a baby, contact a health care provider for any unexplained bleeding, seizures or abnormal behavior, and get emergency medical care right away if symptoms are severe. [1] In the US, call 911 for an emergency. In adults, unexplained bruising or bleeding also needs a clinician's assessment. MedlinePlus says people with vitamin K deficiency are often more likely to have bruising and bleeding. [2] Do not treat bleeding with supplements.

What vitamin K does

MedlinePlus calls vitamin K the clotting vitamin: the body needs it to make clotting-factor proteins in the liver. [2] Vitamin K is also made by bacteria in the lower intestine. [2] MedlinePlus says deficiency is very rare. [2]

Newborns: vitamin K deficiency bleeding (VKDB)

MedlinePlus explains that vitamin K does not move easily across the placenta, bacteria that help make it are not yet present in a newborn's gut, and mother's milk contains little. [1] It groups VKDB into three categories: immediate-onset (within 48 hours, usually linked to the mother's anti-seizure or blood-thinning medicines), early-onset (1 to 14 days, usually in breastfed infants who did not get a vitamin K shot) and late-onset (2 weeks to 6 months, with a higher rate of bleeding inside the skull). [1]

Prevention in the US: the American Academy of Pediatrics recommends a vitamin K shot for every baby immediately after birth. [1] A 2022 AAP statement says intramuscular vitamin K has been standard of care since 1961, and that VKDB incidence appears to be rising because of parental refusal and the lower efficacy of alternative methods. [3]

Prevention in England: an NHS hospital trust leaflet says the Department of Health recommends that all newborns be given vitamin K, that without a supplement VKDB occurs in about 1 in 10,000 births, and that one dose can reduce this to about 1 in 100,000. It describes injection as the most effective method, with oral dosing as the alternative. [4] MedlinePlus also says oral vitamin K must be given more than once and does not appear to be as effective as the shot. [1] Local practice differs, so the maternity team is the place to ask. See Vitamin D and vitamin K for newborns and breastfed babies.

Risk factors listed in that leaflet include prematurity, instrument-assisted or caesarean birth, liver disease, an unwell baby, and a mother who took anti-seizure, anti-tuberculosis or anticoagulant medicines in pregnancy. [4] Parents who have concerns should talk to their midwife or pediatrician.

Adults and older children

Vitamin K deficiency occurs when the body cannot properly absorb the vitamin from the intestinal tract, and can also follow long-term antibiotic treatment. [2] MedlinePlus lists, for any age, alpha1-antitrypsin deficiency, biliary atresia or other cholestatic liver disease, celiac disease, cystic fibrosis or other pancreatic insufficiency, prolonged diarrhea, hepatitis and inflammatory bowel disease as problems that raise risk. [1]

Medicines: warfarin works against vitamin K, so MedlinePlus advises keeping vitamin K intake constant day to day and asking your provider whether to monitor foods containing it. [2] See Vitamin K and Foods high in vitamin K. Never change a prescribed blood thinner or vitamin K intake on your own: talk to your anticoagulation clinic or pharmacist.

Intake reference

The NHS says adults need approximately 1 microgram a day of vitamin K per kilogram of body weight, and that a varied diet should provide it (UK, page reviewed 2020). [5] Other countries publish different figures, so see RDA, AI, DV and UL.