There seems to be no particular benefit to giving every infants vitamin K to prevent haemorrhagic disease of the newborn.
This vitamin began to be given to newborns as a just in case measure in the Fifties, after it was discovered that a deficiency of vitamin K, which assists in blood clotting, was the cause of various kinds of bleeding, including from circumcision, in otherwise healthy babies.
Vitamin K is normally manufactured in a healthy gut. As newborn babies have very low concentrations of it at birth, they rely on it in the diet.
A study in the British Medical Journal attempting to compare vitamin K shots with oral administration was surprised to find that bleeding was rare in the first week of life when no vitamin K was given. "This contrasts with a prevalence of biochemical deficiency of vitamin K over 50 per cent in this population," said Rudiger von Kries in an accompanying editorial. In other words, the usual methods of measuring vitamin K might not be sufficient.
If no newborns in Britain were to receive vitamin K, researchers estimate that only 40 would die from a brain haemorrhage.
Researchers also add, almost as an afterthought, that it might be a good idea if we study the potential side effects of giving vitamin K so early.