The definition of anemia is essential to clinical practice and its epidemiologic understanding, in order to properly plan and monitor public health interventions. 1 In 1968, WHO suggested widely used anemia criteria: hemoglobin levels less than 11 g/dl throughout the pregnancy, stratifying the disorder according to its severity into mild (10-10.9 g/dl), moderate (7-9.9 g/dl), and severe (<7 g/dl). 2 Despite this, it is physiologically known that hemoglobin levels tend to decrease during the first trimester, stabilize during the second and finally increase during the third, so that its average concentration distributes itself in the shape of an "U." 3,4 Taking this into consideration, the US Center for Disease Control and Prevention (CDC), in 1989, set the following diagnostic criteria for anemia: hemoglobin less than 11 g/dl during the first and third trimesters and less than 10.5 g/dl during the second trimester. 3,4