Objective: To investigate the selenium glutathione and glutathione peroxidase (glutathione-Px) levels in blood in women who experience miscarriage., Design: An observational study., Participants: Forty women with miscarriage occurring in the first and second trimesters., Methods: Concentrations were measured in whole blood and plasma. Glutathione was measured in red cells and glutathione-Px activity was measured in the red cells and plasma. The results were compared with 36 women in the same period of viable pregnancy and 28 age-matched, healthy, non-pregnant controls., Results: The selenium concentrations in whole blood and plasma of women following abortion were the same as in viable pregnancy, but were significantly lower compared with controls. The glutathione levels were significantly higher in women with miscarriage compared with viable pregnancies and with non-pregnant women. Red cell and plasma glutathione-Px activities of women who had had a miscarriage were significantly lower than in both normal pregnancies and the control group., Conclusion: The decreased activities of the antioxidant enzymes, red cell and plasma glutathione-Px, may play an important role in the aetrology of spontaneous abortion.