Objective — to compare the antioxidant status of blood in women optimal and late reproductive age in 1-trimester spontaneous and induced pregnancy. Material and methods. A total of 50 women in the first trimester: I (Summary) — 25 women with singleton induced by pregnancy, older reproductive age (37.3±0.6 years). II (Control) — 25 women with spontaneous pregnancies and optimal reproductive age (25.2±2.1 years). Determination of the total antioxidant status (AOC), ceruloplasmin, glutathione reductase activity in the venous serum performed on an automated analyzer using standardized test systems. The content of low and medium molecular mass in serum and erythrocytes — method M.Ya. Malakhova. Statistical analysis of the data made using Statistica for Windows 7.0 application package, by statistical hypothesis testing was performed using Student’s t-test. Differences were considered significant at p<0.05. Results. In nulliparous older reproductive age in the first trimester induced pregnancy indicators of antioxidant system (ceruloplasmin, glutathione reductase activity, total antioxidant status) lower than in the control group, which indicates a decrease in the adaptive capabilities of the organism and higher sensitivity to oxidative stress in these women however, the state of POL-AOC system in this period was balanced and laboratory signs of endogenous intoxication (the content of low and medium molecular mass) was found. Conclusion. Thus, the definition of indicators of antioxidant status the content of low and medium molecular mass should be used for early detection of pre-and a pathological condition associated with a violation of free radical metabolism and the development of endogenous intoxication, especially in older patients of reproductive age.