GSTM1 and hemorrhage: Spinal anesthesia (OR, 0.71; 95% CI, 0.56–0.90; p = 0.004) was an independent predictor for significant hemorrhage, i.e., in patients who had spinal anesthesia, the risk of an Hb drop > 20 g/L was 0.71 times lower compared with patients who had general anesthesia.