Lipid peroxidation, antioxidant defence and acid-base status in cord bloodat birth: The influence of diabetes

Pregnancy complicated by poor control of diabetes is associated with a high er risk of embryopathies, spontaneous abortions and perinatal mortality. A number of authors suggest an involvement of reactive oxygen species (ROS) i n diabetic pregnancy. Determining lipid peroxidation products (LP), scaveng ing enzyme activities and the umbilical cord blood's acid-base balance may contribute to an adequate diagnosis of the neonate at birth. Nevertheless, such measurements seem to have limited Value in practical clinical routine. The present study evaluates LP, antioxidant defence and acid-base status r elated to diabetic pregnancy. Twenty- eight women with type 1 diabetes (PGD M), 19 with gestational diabetes (GDM) and 13 control cases were investigat ed. An additional control group consisted of 15 healthy patients with negat ive diabetic history: all women underwent vaginal delivery. Immediately aft er delivery cord blood samples and placental tissue were collected for malo ndialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) determi nation. Additionally, pH, pCO(2), pO(2) and base excess were measured in bo th vessels and compared to identify and exclude double venous samples. MDA levels in both cord blood and placental homogenates were significantly high er in both pregestational and gestational diabetic groups, but SOD activity was significantly diminished. Cord blood GSH was markedly elevated in PGDM and GDM. We have also shown significant differences in acid-base parameter s in infants of PGDM group. Statistical analysis was performed using the Ma nn-Whitney U-test. These findings indicate an excessive oxidative stress in pregnancy complicated by diabetes mellitus. Evaluating LP products and sca venging enzyme activities may be valuable, sensitive indexes of fetal/neona tal threat in diabetic pregnancy in humans. Since oxidative stress is an im portant pathway for fetal injury, we believe that obtaining adequate measur ements at the time of birth would contribute to clarifying the fetal/neonat al status in a medical and legal context and might be of value in altering therapy in newborn infants.