Erythropoiesis in pregnancy.

There is a dramatic increase in total blood volume during healthy pregnancy. The disproportionate expansion in plasma volume (50%) and red cell mass (18-25% depending on iron status) results in a decrease in haemoglobin concentration maximal at 32 weeks gestation. This should not fall below 11 g/dl at any time during pregnancy. Deficiency of essential haematinics arising from increased requirements and inadequate intake may have far reaching effects on mother, fetus and neonate which bear no relationship to the impaired oxygen carrying capacity of the reduced cell mass. Pathological anaemia of pregnancy is due to over 90% of cases to iron deficiency associated with depleted stores and deficient intake. The single largest demand for iron arises from the increased red cell mass under the influence of erythropoietin. Tissue enzyme malfunction occurs even in the very first stages of iron deficiency before significant anaemia develops. Increased blood loss at delivery and preterm birth are observed associated complications. Off-spring of iron deficient mothers have decreased iron stores and may develop anaemia in the first year of life. Studies have shown behavioural abnormalities in children with iron deficiency and poor performance in the Bayley Mental Developmental Index. The poor performance in mental and motor development can be improved to the level of iron-sufficient infants by treatment with ferrous sulphate. Folate deficiency often accompanies iron deficiency as they are both associated with a poor diet. The haematological effects of folate deficiency are usually masked by iron deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)