These predictors include: previous PPH [10, 18–20], mother’s age 35 years or above [19–22], hypertensive disorders in pregnancy [7, 10, 22, 23], prolonged labour or complication during labour [7, 20, 24, 25], operative vaginal delivery and instrumental vaginal deliveries [20, 26, 27], multiparity [21, 24, 25], multiple pregnancy [10, 19], Hb less than 10gr/dL on admission to labour, ante-partum anaemia [23, 26–28], fundal height of 38cm or above or large baby [19, 23, 26], placenta praevia [29, 30] and induction of labour [25, 31]. This evidence concerns the gene GSTM1 and pulmonary arterial hypertension.