[Hemoglobin, iron deficiency and anemia in pregnant women. Diagnostic aspects].

Normal haemoglobin concentration in the trimesters of pregnancy can be considered to be 11-13 g/100 ml, 10-13 g/100 ml and 11-14 g/100 ml, respectively. High and low haemoglobin levels both indicate important pathophysiological changes. The authors discuss the use of serum-ferritin (S-ferritin), mean corpuscular volume (MCV) and erythrocyte protoporphyrin as diagnostic tools. S-ferritin, which is a reliable indicator of the iron status in the first trimester, becomes less reliable after the 20th week due to the physiological dilution of the plasma and a concurrent fall in haemoglobin and S-ferritin. Erythrocyte protoporphyrin is not influenced by the plasma dilution and can be used as a supplement to S-ferritin to assess iron deficiency. MCV can also be used to characterise the iron status. Decreases in MCV take time, however, which makes clinical interpretation difficult. S-ferritin measurement early in pregnancy is a reliable parameter for judging whether iron supplementation is necessary. Even if S-ferritin is influenced by the plasma dilution, a concentration below 15 microgram/l indicates iron deficiency in all stages of pregnancy.