The vitamin K controversy.

Discussion about the efficacy and safety of vitamin K prophylaxis has recently restarted. In this review, new developments in diagnosis of vitamin K deficiency (including vitamin K plasma levels and protein induced by vitamin K absence [PIVKA]-II detection) and therapy of early, classic, and late hemorrhagic disease of the newborn are highlighted. Special attention is brought to the efficacy of preventing early and late hemorrhagic disease. The recently described association between intramuscular vitamin K administration and cancer is debated. The very high plasma levels, the intramuscular injection itself, or the adjuvants in the solution might all be responsible. These factors are all absent in oral administration. Therefore, we recommend repeated oral administration for preventing classic and late hemorrhagic disease of the newborn. Additionally, we recommend maternal supplementation of vitamin K for preventing early hemorrhagic disease of the newborn, especially when the mother is using medications that interfere with vitamin K metabolism.