Changes in red blood cell oxygen transport in diabetic pregnancy

Parameters of red cell oxygen transport were studied in 23 nonsmoking, insulin-dependent diabetic women and 20 nonsmoking healthy women late during pregnancy. In the pregnant diabetic women, arterial oxygen saturation (SAT) and arterial oxygen tension were significantly decreased. SAT correlated inversely with hemoglobin Alc (Hb Alc) (diabetic women: r = -0.43, p less than 0.05; total material: r = 0.66, p less than 0.001). Red blood cell 2,3-diphosphoglycerate (2,3-DPG) was significantly increased in the pregnant diabetic women (p less than 0.01), but the 2,3-DPG-induced change in hemoglobin-oxygen affinity was impaired. P50 (oxygen affinity, i.e., Po2 at 50% oxygen saturation) at actual pH correlated inversely with Hb Alc of the diabetic women (r = -0.45, p less than 0.05). The suggestion is made that, in diabetic pregnancy, particularly in poorly regulated cases, fetal hypoxia may be an important factor of the increased risk of intrauterine fetal death.