Monitoring oral iron therapy with protoporphyrin/heme ratios in pregnant women

Abstract

Assessment of the efficacy of iron therapy has usually been done in populations/patients by monitoring changes in hemoglobin concentration, serum iron, percent transferrin saturation, and serum ferritin. In this study the protoporphyrin heme (P/H) ratio (a measure of free erythrocyte protoporphyrin) was measured before and after iron therapy in three groups of pregnant women, who received 60 mg (group A), 120 mg (group B), and 240 mg (group C) of elemental iron with folic acid (0.5 mg) per day for a period of 12 weeks, to evaluate its efficacy to monitor iron therapy. The three groups were comparable regarding the initial mean Hb concentration and serum ferritin levels. The initial mean P/H ratios were markedly elevated in all three groups and were different in the three groups, being highest in group A (113.2+/-92.6), intermediate in group B (87.5+/-62.5), and lowest in group C (69.8+/-43.3). The initial P/H ratio was significantly higher in group A than in group C (p<0.05). This probably affected the efficacy of iron therapy in the three groups. The P/H ratio decreased significantly in each of the three groups after iron therapy (A and B: p<0.001; C p<0.01). Mean Hb concentration and serum ferritin increased in all three groups post therapy; however, the magnitude of change in P/H ratio in all three groups was much greater. This indicated that the predominant contributory factor for anemia was iron deficiency in this group of pregnant women. Serum iron and percent transferrin saturation are difficult to interpret in our population, as iron is freely available over the counter and is prescribed as soon as anemia is detected in patients; therefore, the reduction in P/H ratio may be used to monitor response to iron therapy in population groups.