Assessment and Differential Diagnosis of Iron-Deficiency Anaemia during Pregnancy

Anaemia is one of the most common risk factors in the area of obstetrics and perinatal medicine. During pregnancy and in the puerperium it is associated with an increased incidence of both maternal and fetal morbidity and mortality, the extent of which is dependent upon the severity of anaemia and the resulting complications.

In order to correctly diagnose the type and degree of anaemia, a prerequisite for selection of the proper therapy, one must first of all correctly differentiate between ‘relative anaemia’, the physiological anaemia of pregnancy caused by the normal plasma volume increase during pregnancy, and ‘real anaemias’ with various different pathophysiological causes. When defining the haemoglobin cut-off value for anaemia in pregnancy, the extent of plasma volume changes with respect to gestational age must be taken into consideration. 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 anaemic condition that should be further clarified. Among the most important differential diagnoses for anaemia during pregnancy are: (i) iron-deficiency anaemia and the preceding stages of iron depletion; (ii) haemoglobinopathies (thalassaemia, sickle cell anaemia); (iii) anaemia resulting from infections, e.g malaria; and (iv) renal anaemia, for example in pregnant women with renal insufficiency or a renal transplant.