The MA of Haider et al.,12published in 2013 (Table 1), aimed to summarize the evidence on the association of maternal anemia and iron supplementation in pregnancy with maternal hematological effects and adverse outcomes in pregnancy; it also evaluated the potential relationship between iron exposure (regarding dose, duration of use and hemoglobin [Hb] concentration) and maternal outcomes. The gene discussed is GSTM1; the disease is anemia (phenotype).