[Selenium and glutathion peroxidase enzyme levels in diabetic patients with early spontaneous abortions]

The incidence of spontaneous abortions in women with type 1 diabetes mellitus varies between 10-30%. The etiology of this is still unclear despite numerous experimental studies. Pregnancy is a condition of increased oxidative stress due to impaired balance between pro- and antioxidants. Glutathion and related enzymes perform the best antioxidant protection. Some authors point to a possible correlation between spontaneous abortions and low plasma Se levels as well as low intracellular activity of glutathion peroxidase enzyme. Others report that Hb A1-c, values over 1SD above normal increase the risk of spontaneous abortions with 3% and Hb A1-C values between 10-12% are critically high for the occurrence of spontaneous abortions. The purpose of the study was to evaluate the levels of Se and glutathion peroxidase enzyme (Gl-Px) in pregnant women with type 1 diabetes mellitus in the first trimester of pregnancy and to find out is there a correlation between glycemic control of diabetes and the incidence of spontaneous abortions.

75 pregnant women enrolled in an- 1 year prospective study divided in 3 groups according to pregnancy outcome: gr. 1 - n = 30 with type diabetes mellitus, no abortions, gr.2 - n = 16 with type diabetes mellitus with first trimester spontaneous abortion and gr. 3 - n = 29 healthy pregnant women. Women with type 1 diabetes mellitus were divided into three subgr. according to glycemic control - subgr. 1 - n = 12 (Hb A1-c < 7%), subgr.2 - n = 18 (Hb A1-c > 7< 8%), subgr.3 - n = 16 (Hb A1-c > 8%). Gl-Px activity was determined in Er hemolisate with test reagents of Randox Ransel, with ref.values 27.5 - 73 U/g Hb. Selen concentration was determined in whole blood sample by atomic absorption spectrophotometry with ref. values 0.12-1.1 micromol/l. HbA 1-C was measured by affinity chromatography with ref. values 4.5-6.3%. Statistical methods used were: dispersion, correlation analysis - SPSS package version 11.01.01.

Basic Se levels were low in all pregnant women in early pregnancy. The metabolic control level did not influence the levels of Se in pregnant women with diabetes mellitus type1. Gl -Px activity was within the normal limits in all women. There was no correlation between Se levels and Gl -Px activity in pregnant diabetics with and without abortions. There was a correlation between Se levels and Gl -Px activity only in healthy pregnant women. Pregnant women with poor glycemic control had higher incidence of spontaneous abortions.

We could not support the hypothesis of reduced antioxidant protection (low Se and Gl-Px levels) as a causative factor in the pathogenesis of spontaneous abortions in diabetic patients. Our study results showed that poor metabolic control of diabetes (high Hb A1-c) in the first trimester of pregnancy had a primary role in the occurrence of early abortions. We could speculate that the early hyperglycemic maternal-fetal environment most probably plays a role of an additional stress to the developing embryo.