The variations of haemoglobin (Hb) levels throughout pregnancy have seldom been investigated, although an early study in Papua New Guinea, where pregnant women received neither malaria prophylaxis nor haematinics, reported that the differences in Hb levels between malaria-positive at booking and malaria-negative at delivery were higher in primigravidae than in multigravidae [5]. The gene discussed is GSTM1; the disease is malaria.