In this study, the overall poor Hb response to IFA supplementation among anemic pregnant women was 47.3%.There were different factors assessed for poor Hb response, including; the participants were from rural area, parity (multiparous), intestinal parasite infection, duration of IFA supplementation less than five month, meat and vegetable consumption less than two times in a week, HBV&HCV positive, stage of pregnancy and coffee drinking habit were associated with poor hemoglobin response to IFA supplementation. The gene discussed is GSTM1; the disease is parasitic intestinal disorder.