Author: Victora, C.; UNICEF NYHQ
Vitamin K prophylaxis for newborn infants is widely used in most industrialized countries as well as in hospital settings in many less developed countries (LDCs) in order to prevent haemorrhagic disease of the newborn (HDN). This syndrome mostly affects exclusively breastfed babies. This review is aimed at estimating the magnitude of this problem in LDCs, assessing the need for prophylaxis, its cost-effectiveness and feasibility, and investigating whether current recommendations for breastfeeding promotion should be revised.
Purpose / Objective
This review is aimed at filling an information gap. Its objectives include:
- To estimate the magnitude of vitamin K deficiency and its consequences, among infants from less developed countries
- To examine the role of exclusive breastfeeding in vitamin K deficiency and to assess whether breastfeeding promotion strategies should be modified accordingly
- To establish whether there is a need for vitamin K prophylaxis in less developed countries
- To discuss cost and feasibility issues associated with proposing universal vitamin K supplementation
Review of relevant literature.
Key Findings and Conclusions
Vitamin K is essential for the normal clotting of blood. Newborn infants have low vitamin K levels and HDN may occur within the first 24 hours of life (early HDN), between days 1 and 7 (classic HDN) or from 2-12 weeks (late HDN). The latter is of greatest concern because up to one quarter of affected babies may die from brain haemorrhage and up to one half of the survivors may show permanent neurological disabilities.
Classic and late HDN may be effectively prevented by vitamin K administration soon after birth. Intramuscular vitamin K is highly effective and oral dosage schemes have also been used in several developed countries. A single, oral dose provides partial protection against late HDN but full protection requires multiple doses. Intramuscular vitamin K has rare, localized side effects at the site of the injection. Recently, there has been major concern about the possibility of an association with childhood cancer. Early studies showing such an association, however, have not been confirmed although some degree of controversy remains.
The incidence of late HDN in developed countries ranges from about 4 to about 25 per 100,000 births. No population-based studies are available from less developed countries but there are several reports of this disease, particularly from South and Southeast Asia. The main risk factors for late HDN are gender (males are at a higher risk), warm environmental temperatures and breastfeeding. Breast milk contains low concentrations of this vitamin and the gastrointestinal tracts of breastfed babies are poor in the type of bacteria that help synthesize vitamin K. These infants have up to 20 times greater risk of late HDN than formula-fed babies.
Due to the lack of adequate data from LDCs, three incidence scenarios are proposed. Our best estimate is that the warm temperatures and high frequency of breastfeeding will lead to a four-fold increase in incidence relative to industrialized countries. This implies an incidence of 28 per 100,000 births and will be our intermediate incidence scenario. The low incidence scenario assumes that seven out of each 100,000 babies will be affected, corresponding to the median value from developed country studies. The high incidence scenario uses a rate of 72 per 100,000, based on a single hospital-based study from Thailand.
The methodology developed by the World Bank for calculating the loss of DALYs (disability-adjusted life years) was applied to these three scenarios. Late HDN would account for the loss of about one million DALYs among the 126 million children born in 1993, under the intermediate scenario. This represents about 0.23 per cent of all DALYs lost for under-five boys and 0.13 per cent for girls. The corresponding figures would be 0.06 per cent for boys and 0.03 per cent for girls, under the low scenario; and 0.59 per cent and 0.34 per cent, respectively, under the high scenario. For the sake of comparison, diarrhoea and pneumonia each account for about 15-20 per cent of all DALYs lost. Comparison of the DALYs lost due to HDN with those due to infectious diseases - against which breastfeeding provides substantial protection - shows that concern with vitamin K deficiency should not be allowed to affect current efforts in breastfeeding promotion.
Based on an estimated cost of US$1.00 per injection, each DALY saved would cost US$133, under the intermediate scenario. This implies a moderate level of cost-effectiveness, inferior to that of most common causes of lost DALYs in childhood. The feasibility of giving vitamin K prophylaxis along with BCG vaccine is discussed.
Vitamin K deficiency fulfills the criteria for constituting a public health problem. Although its incidence is low, its severity and case-fatality are often high. It can be effectively prevented by a relatively safe intervention with moderate cost-effectiveness. Universal recommendations for prophylaxis cannot be made at this stage and decisions must be taken on a national basis.
There seem to be three different situations. In the least developed countries, the logistics of delivering vitamin K to newborns would be very complex and there are a number of more cost-effective interventions that are required due to the high burden of disease. In middle-income countries, most births already occur in a hospital and the burden of disease is lower, so that prophylaxis is probably recommended. In industrialized countries, there are strong reasons for supporting universal prophylaxis.
There are many research gaps regarding vitamin K deficiency. Surveys are urgently required for estimating the incidence of HDN from hospital data as well as using biochemical markers of deficiency. Research is also needed to assess the effectiveness of maternal supplementation as a means of preventing disease in the newborn.
PDF files require Acrobat Reader.
Health - Micronutrients IDD