GSTM1 and anemia (phenotype): Anaemia was categorized as mild (haemoglobin [Hb] of 10.0–10.9 g/dL for pregnant women and 11.0–11.9 g/dL for non-pregnant women), moderate (Hb of 7.0–9.9 g/dL for pregnant women and 8.0–10.9 g/dL for non-pregnant women), and severe (Hb <7.0 g/dL for pregnant women and <8.0 g/dL for non-pregnant women).