Anemia is a condition in which the number of red blood cells (RBC) is insufficient to meet the body's physiological needs for oxygen transport. A limiting factor for the erythrocyte mass increase is iron deficiency, which can also have a negative impact on the pregnancy's prognosis. The most frequent pathogenic cause of anemia in pregnancy is iron deficiency anemia (IDA). Biochemical tests such as serum iron concentration, total iron binding capacity (TIBC), transferrin concentration, and ferritin concentration are decreased in iron deficiency anemia. In clinical practice, iron deficiency is defined as low serum ferritin or a decreased percentage of transferrin saturation by iron. Usually, the diagnosis begins with the determination of serum ferritin. Although iron supplementation for iron deficiency is advised as soon as the condition has been diagnosed, prophylactic iron delivery is still under discussion. In patients for whom oral iron is ineffective or contraindicated, intravenous iron can be used to restore lost iron. Keywords: iron deficiency, iron deficiency anemia, pregnancy, iron supplementation