G6PD and hydrops fetalis: To further identify which metabolic enzyme generating NADPH is affected by HF treatment, glucose-6-phosphate dehydrogenase (G6PD, EC: 1.1.1.49) and 6-phosphogluconate dehydrogenase (PGD, EC: 1.1.1.44) in oxidative branch of PPP, malic enzyme (ME1, EC: 1.1.1.40) in pyruvate metabolism and isocitrate dehydrogenase (IDH1, EC: 1.1.1.42) in tricarboxylic acid (TCA) cycle were examined.