GSTM1 and anemia (phenotype): Univariate analysis showed that post-operatively, women in the Mandated IOCS group had higher post-operative Hb values, 111 g/L vs 102 g/L (p < 0.001) (despite similar pre-operative Hb, 125 g/L vs 124 g/L), had significantly lower rates of anemia, 48% vs 78% (p < 0.001) and less often exposed to post-partum intravenous iron, 11% vs 3% (p < 0.001) (Table 2).