GSTM1 and anemia (phenotype): In addition, primigravida (AOR = 0.567, P-value<0.001) and multigravida (AOR = 0.673, P-value = 0.001) were associated with lower risk of anemia, while gestational age was associated with decreased risks of high Hb levels (AOR = 0.980, P-value = 0.009) (Table 4).