Anaemia in pregnancy continues to be a major public health problem in the world. Despite decades of proposed solutions, women in developing countries are still suffering the effects of having to go through a pregnancy in an anaemic state. Based on 1988 data, the World Health Organisation estimated that up to 56% of all women living in developing countries are anaemic ([Hb] < 11 g/dL), compared with 18% in industrialised countries1. The greatest burden of anaemia is borne by Asia and Africa where it is estimated that 60% and 52% of women, respectively, are anaemic, and between 1% and 5% are severely anaemic ([Hb] < 7 g/dL). In this issue van den Broek and colleagues (pages 445–451)2 report the prevalence of anaemia in pregnancy in Malawi and refer to recent data from other sub-Saharan countries, confirming that the problem has not changed during the last decade.
Worldwide nearly 600,000 women between the ages of 15 and 49 die each year as a result of complications arising from pregnancy and childbirth, more than 95% of these maternal deaths being in developing countries. The proportion of maternal deaths due to anaemia has been estimated for countries with reliable data: India (16%), Kenya (11%), Nigeria (9%) and Malawi (8%)3. For the rest of the developing world, we can only assume that anaemia contributes to the unacceptably high maternal death rates. Anaemia may act as an underlying factor which places women at a higher risk of dying from one of the five major causes of maternal mortality (e.g. haemorrhage, eclampsia, abortion, obstructed labour and sepsis), or may be directly responsible as an independent factor.
Although there are many causes of anaemia in pregnancy, nutritional iron deficiency anaemia is the main one in the developing world, other common causes being malaria and hookworm infection. Recent guidelines on the prevention and treatment of iron deficiency anaemia (WHO/UNICEF/INACG) have recognised the many causes of anaemia in pregnancy often occurring in the same woman, and have suggested appropriate treatments accordingly4. These guidelines recommend that all pregnant women in developing countries should receive routine daily supplementation of iron (60 mg) and folic acid (400 μg), and should be considered for preventative measures against malaria and hookworm. Universal prophylaxis with iron and folic acid is justified since in developing countries the physiological requirements for iron and folic acid in pregnancy are difficult to meet with most diets. Prophylaxis with iron and folic acid is recommended for at least six months in pregnancy, and if this cannot be achieved due to late booking, a higher dosage of 120 mg of elemental iron should be given during pregnancy and in the postpartum period.
Hookworm infection is likely to be an important cause of anaemia in pregnancy in areas where the parasite has reach a prevalence of 20% and 30%. It is estimated that each year 44 million pregnant women are infected with hookworm. It has been shown that pregnant women given anthelminthic therapy, iron and folic acid have a better response than those receiving only iron and folic acid4. Mebendazole, albendazole, levamisole and pyrantel may be all safely administered to pregnant women after the first trimester4.
Malaria due to Plasmodium falciparum may cause severe anaemia in pregnancy. Women in their first and second pregnancies and living in an endemic area are at a higher risk of acquiring malaria than nonpregnant women or multigravidae, due to the reduction of an appropriate immune response to the malarial parasite. Given the high maternal and infant mortality associated with malaria in pregnancy, antimalarial therapy should be given to all primigravidae and secundigravidae in highly endemic areas5. A recent randomised trial has shown the effectiveness of using routine treatment with sulphadoxine and pyrimethamine in pregnant women6.
Breastfeeding during the first six months after delivery reduces maternal iron loss, while delayed cord clamping is thought to prevent iron deficiency in infancy. The routine use of oxytocin during the third stage of labour is advocated for the prevention of postpartum haemorrhage7. Prevention of the adverse effects of anaemia in pregnancy in developing countries requires not only nutritional supplementation, but also adequate obstetric care.
Van den Broek et al.2 studied at risk groups in southern Malawi in order to justify targeting treatment rather than giving iron to all pregnant women. The authors were not able to justify targeting at risk pregnant women or other groups of women of reproductive age, concluding that universal prophylaxis of anaemia in pregnancy was the most effective measure. Their conclusion that routine supplementation of all pregnant women living in developing countries with iron and folic acid is justified agrees with recent WHO policies. However, the WHO/UNICEF/INACG guidelines state that in areas where iron deficiency is highly prevalent, other groups such as adolescent girls can also benefit from supplementation and should be included in programmes to prevent anaemia.
Researchers are now investigating whether iron and folic acid should be part of a multiple supplement for pregnant women. A tablet consisting of vitamins A, E, C; iron, zinc, iodine, folic acid, copper, riboflavin, pyridoxine and hydroxycobalmin is presently being tested in field trials. Preliminary results have indicated possible benefit of other micro-nutrients in anaemia. In countries such as Nepal, where deficiency in vitamin A is prevalent, iron deficiency anaemia in pregnancy was reduced by 9% among women receiving vitamin A8. Since dietary quality rather than quantity is the major determinant of nutritional status in women in developing countries, UNICEF and WHO are exploring the optimum composition of iron and vitamin supplementation in pregnancy.
Food fortification programmes may be important in improving not only the nutritional status of the population, but in particular vulnerable groups such as women of reproductive age and children below the age of five. Fortification of food vehicles with absorbable forms of iron is used by some countries to prevent iron deficiency anaemia. Fortification of food, such as wheat flour and maize, is technically simple and has been achieved successfully in several countries in Latin America and in the Caribbean. Other methods of iron fortification target widely used condiments, such as fish sauce, curry powder, salt and sugar. One of the limitations of food fortification programmes is that the fortified products are not always consumed by the most needy in the population, due to the cost, lack of education and difficulties of distribution.
Genetically modified foods are presently attracting a great deal of attention from the media and from environmentalists. We should acknowledge their potential for improving the nutritional status of populations living in deprived situations. The amount of phytate in the grain renders rice a poor source of iron because phytate blocks the absorption of iron. Rice has been genetically modified to decrease the amount of phytate, to increase the amount of iron stored by the grain, and to increase the amount of the amino acid cysteine, which aids absorption of iron from the intestine. Furthermore, rice can be genetically altered to produce enough beta carotene—which is converted to vitamin A in the body— to supply all of a person's requirements for vitamin A. Although research into genetically modified plants is still in its infancy and questions regarding the potential dangers as well as benefits still need to be answered, this technology offers hope to people still suffering from these common forms of nutritional deficiencies.
In conclusion, a pregnant woman should be free from nutritional deficiencies and parasitic infections, and have adequate obstetric care. Public health policies to reduce the prevalence of anaemia in pregnancy and its adverse effects on the mother and her infant should include three strategies: 1. introduce and sustain a programme in pregnancy of supplementation with iron and folic acid, and prophylaxis against parasitic disease; 2. improve obstetric care; and 3. adopt fortification of food in order to improve the diet of women and children who are most at risk of nutritional deficiencies.