<qa>  What was the Hb concentration increased by day 40?4. Sample size calculation: It was reported that treatment with oral iron for anemia in postpartum women increase the Hb concentration by 49.3 by day 40. Combined with etiological treatment, Ejiao compound used to treat anemia in non pregnant population for three months, the Hb concentration increased by 66.9. Basing on the results of literatures mentioned above, the investigators suppose that the difference of Hb concentration between patients only receiving the Ejiao compound for 4 weeks and patients only receiving oral iron for 4 weeks would be 25.0. The α-value is set at 0.05 and the test power is 0.90. The final sample size should be 68 in each group. With an anticipated dropout rate of 20 during the follow-up, the initial sample size for each group should be 85, and 170 in total for two groups. 