To this end, some guidelines note that pre- and post-delivery Hb levels should be taken into consideration when diagnosing cases of PPH and providing follow-up care.9,23 In high elevation settings, where Hb concentrations are notably higher, altitude-specific haemoglobin cut-offs for defining iron deficiency deserve attention.24 This study was designed to compare the proportions of women with Hb levels <9 and <11 g/dl between study groups. This evidence concerns the gene GSTM1 and pulmonary arterial hypertension.