Assessment and differential diagnosis of iron-deficiency anaemia during pregnancy

Anaemia is one of the most common risk factors in the area of obstetrics an d perinatal medicine. During pregnancy and in the puerperium it is associat ed with an increased incidence of both maternal and fetal morbidity and mor tality, the extent of which is dependent upon the severity of anaemia and t he resulting complications. In order to correctly diagnose the type and degree of anaemia, a prerequisi te for selection of the proper therapy, one must first of all correctly dif ferentiate between 'relative anaemia', the physiological anaemia of pregnan cy caused by the normal plasma volume increase during pregnancy, and 'real anaemias' with various different pathophysiological causes. When defining t he haemoglobin cut-off value for anaemia in pregnancy, the extent of plasma volume changes with respect to gestational age must be taken into consider ation. It has been found that haemoglobin values <110 g/L in the first and third trimesters, and <105 g/L in the second trimester, may point to an ana emic condition that should be further clarified. Among the most important d ifferential diagnoses for anaemia during pregnancy are: (i) iron-deficiency anaemia and the preceding stages of iron depletion; (ii) haemoglobinopathi es (thalassaemia, sickle cell anaemia); (iii) anaemia resulting from infect ions, e.g malaria; and (iv) renal anaemia, for example in pregnant women wi th renal insufficiency or a renal transplant.