Proper identification of iron deficiency anemia in pregnant women is essential in the differential diagnosis of hematologic disorders, therefore, early detection and timely, and monitoring to assess the efficacy of iron therapy are essential parameters to ensure an adequate state of health of the pregnant mother and the good progress of her pregnancy. Classical parameters have been established to measure the degree of therapeutic response in pregnant women with iron deficiency anemia, such as ferritin, transferrin, and others, however, its high cost and longer processing time not make them ideal markers for such purpose. In Ecuador there are no previous reports regarding the assessment Reticulocyes Fluorescence Index and Reticulocyte hemoglobin load. It poses a clinical trial evaluation uncontrolled diagnostic test, in order to determine that the use of fluorescence index and load Reticulocyte Hemoglobin the (Chr) measured by automated hematological parameters are valid markers for diagnosis and assessment of the impact interventions ferrous sulfate supplementation in a representative sample of 84 pregnant women which will be recruited at 20 weeks of gestation, with up to 32 weeks and 36 to evaluate the change associated with supplementation on predefined indicators. The prevalence of anemia and / or deficiency will be expressed in percentages with their corresponding confidence interval at 95%. For the inferential analysis was used for intergroup comparisons in the case of qualitative variables t difference of proportions for independent groups and not for quantitative t mean difference prior definition of homogeneity of variance (F test) while for intragroup analysis will be used for quantitative variables paired t and for qualitative variables Chi square McNemmar. For the analysis of correlation between the rate of fluorescence, the reticulocyte Hb and serum ferritin levels will use the Pearson correlation coefficient, and to establish the commonalities between these tests in terms of identification of deficiency, the test will be used Cohen's Kappa also calculated the sensitivity, specificity, predictive values and likelihood ratios, considering as a gold the deficiency of serum ferritin concentrations. For all inferential statistical tests are accepted as valid a significance level of 95% (a = 0.05).