Anemia in pregnancy is defined as first-trimester hemoglobin (Hb) less than 11.0 g/dL, second-/third-trimester Hb less than 10.5 g/dL, and postpartum Hb less than 10.0 g/dL according to guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG), in line with British Committee for Standards in Haematology (BCSH) guidelines [1]. The gene discussed is GSTM1; the disease is anemia (phenotype).