Objective: Pregnancy and mainly its complications are associated with increased oxidative stress. Advanced oxidation protein products (AOPP) can serve as one of its markers. Setting: First Institute of Medical Chemistry and Biochemistry and Institute for Clinical Biochemistry, First Medical Faculty, Charles University; Institute for Care of Mother and Child, Prague. Methods: Together with parameters of prenatal screening, AOPP were measured in the serum of 23 pregnant women in the 2nd trimester of pregnancy. A group of healthy blood donors – women and men was used for comparison. AOPP were determined spectrophotometrically according to Witko-Sarsat (absorbance at 340 nm) and are expressed in chloramin units (mmol/l). Results: Serum AOPP concentrations in pregnant women are significantly higher in comparison with blood donors – women (85.90±18.70 mmol/l vs 57.34±16.31 mmol/l, P<0.0001) but there is no statisticaly significant difference between pregnant women and blood donors – men (85.90±18.70 mmol/l vs 78.60±44.01 mmol/l). AOPP level does not correlate either with the age of pregnant women or with the parameters of prenatal screening (human chorionic gonadotrophin – HCG, alpha-1-fetoprotein – AFP and trophoblast-specific – beta-1-glycoprotein – SP1). Conclusion: AOPP as a marker of oxidative stress is increased in the serum of pregnant women in comparison with women – blood donors but is similar as in men – blood donors which supports the hypothesis of hormonal influence. Nevertheless, AOPP do not correlate with the parameters of prenatal screening (HCG, AFP and SP1).

        Key words: oxidative stress, pregnancy, advanced oxidation protein products