Anaemia in pregnancy is a common and worldwide problem that deserves more attention. For many developing countries, prevalence rates of up to 75% are reported. Anaemia is frequently severe in these situations and can be expected to contribute significantly to maternal mortality and morbidity. After a discussion of definitions, screening for anaemia and prevalence, the relationship between anaemia and maternal mortality and morbidity will be reviewed. Micronutrient deficiency and especially iron deficiency is believed to be the main underlying cause for anaemia. More recently the role of vitamin A deficiency as a contributing factor to anaemia has also been examined. The difficulties of assessment of micronutrient sufficiency or deficiency in pregnancy are described, as is the interaction between infection and micronutrient deficiency states.