A nurse is assisting in the care of a toddler who has been taking oral ferrous sulfate drops for iron deficiency anemia. Which of the following data collection findings indicates that the medication is effective?

Iron deficiency anemia in toddlers is commonly treated with oral iron supplementation such as Ferrous sulfate to restore hemoglobin levels and replenish iron stores. The effectiveness of therapy is evaluated by improvements in oxygen-carrying capacity and resolution of deficiency symptoms. Iron therapy also produces characteristic changes in stool color and consistency due to unabsorbed iron. Monitoring both laboratory values and expected side effects helps determine therapeutic response. Rationale: A. Decreased hemoglobin indicates worsening anemia rather than improvement. Effective iron therapy should lead to an increase in hemoglobin levels over time as iron is utilized for red blood cell production. A decline suggests inadequate absorption, poor compliance, or ongoing blood loss rather than therapeutic success. B. Weight loss is not an indicator of effective iron therapy and may suggest poor nutritional status or another underlying condition. Successful treatment of iron deficiency anemia is associated with improved energy levels and normal growth patterns in toddlers. Continued weight loss would require further evaluation rather than being considered a positive response. C. Tarry, green stools are a common and expected side effect of iron supplementation such as ferrous sulfate. This occurs due to unabsorbed iron passing through the gastrointestinal tract and oxidizing in stool. This is not harmful, but it is often used as an indirect indicator that the medication is being taken and processed by the body. D. Pica, the ingestion of non-food substances such as dirt or ice, is a symptom of iron deficiency anemia rather than an indicator of improvement. Effective iron therapy should reduce or eliminate pica behaviors as iron stores normalize. Persistence of pica suggests that treatment has not yet corrected the underlying deficiency.