Due to the findings that both low and elevated Hb concentrations have been associated with maternal morbidities, the primary objective of this study was to determine the association of iron status and anaemia at early (< 18 weeks) and mid-pregnancy (± 22 weeks) with prehypertension in late pregnancy (± 36 weeks’ gestation). The gene discussed is GSTM1; the disease is anemia (phenotype).