GSTM1 and schistosomiasis: Anaemia occurs when the Hb concentration of a person falls below the lower reference level for the population under study.14,15 The WHO’s normal reference Hb level in pregnant women is ≥11 g/dL.5 Common causes of iron deficiency anaemia in women of childbearing age include poor diet, haemolysis because of parasites such as malaria, schistosomiasis, intestinal parasites such as hookworm, or bleeding during labour.5