Objective: To determine the activity of reactive oxygen species (ROS) during labour by characterizing changes in maternal serum levels of lipid peroxidation end-products – MDA and lipofuscin during labour and the early post-partum period. We also tried to evaluate the relationship between levels of lipid peroxides and some clinical characteristics of labour. Conclusion: Based on our findings we can suggest an increased activity of ROS during labour which is exhibited by increased generation of lipoperoxides. Lipid peroxidation in healthy pregnant women during labour is under a constant control of the antioxidant system. Design: Prospective study. Setting: Department of Obstetrics and Gynaecology LFUK, Bratislava; Department of clinical laboratories, Ministry of defence SR, Bratislava. Methods: Blood samples were obtained from 66 pregnant women with uncomplicated pregnancy at the end of labour and during the early postartum period. The control group consisted of 19 pregnant women delivering by primary Caesarian section. Blood samples were examined for MDA and lipofuscin by HPLC method. We used paired and unpaired Student’s t-test to statistically evaluate our results. Results: MDA and lipofuscin levels in pregnant women delivering spontaneously compared to those delivering by C-section were significantly elevated (P < 0.05). MDA and lipofuscin levels in pregnant women during spontaneous labour or during by C-section compared to the levels in early post-partum period were not significantly increased. We have not found any correlation between the length of the labour and lipoperoxides concentration.

        Key words: labour, reactive oxygen species, lipid peroxidation, oxidative stress