New aspects of vitamin K prophylaxis.

Vitamin K-deficiency bleeding (VKDB) is rare, unpredictable, and life-threatening. Warning signs such as minimal bleeds, evidence of cholestasis, and failure to thrive often are present but overlooked. Therefore VK prophylaxis is necessary, at least for breastfed infants. Most effective is the intramuscular application, which unfortunately has real disadvantages (trauma, poor acceptance by parents) and potential risks due to very high VK levels, since VK affects not only coagulation but all processes associated with carboxylation. Three oral doses of VK protect many babies (2-mg doses giving better protection than 1 mg) but the prevention of VKDB is not assured even with the mixed-micelle preparation. Use of small VK doses either daily or weekly seems to give effective prophylaxis without the adverse effects of intramuscular VK application. The risks of VKDB are minimized if prophylaxis recommendations are followed and if warning signs are recognized and promptly acted upon. The next goal is the search for methods of identifying early the few infants destined to bleed so that targeted prophylaxis can replace the current "prophylaxis for all."