© 2021 Informa UK Limited, trading as Taylor & Francis Group.Objective: The purpose of this study is to evaluate antioxidant balance in pregnant women with meconium-stained amniotic fluid. Methods: Forty pregnant women with meconium-stained amniotic fluid and 40 pregnant women with non-meconium-stained amniotic fluid were included in the study. By checking the ischemia modified albumin (IMA) level and thiol/disulfide homeostasis in the maternal blood during labor and in newborn umbilical cord blood at the first minute after birth, antioxidant/oxidant balance was evaluated. Results: No statistically significant difference was found between the maternal albumin levels. Maternal IMA level was statistically significantly higher in the meconium group than in the control group (p =.045). Maternal native thiol (SH) and maternal total thiol levels were statistically significantly higher in the control group than in the meconium group (p =.042 and p =.009, respectively). No statistically significant difference was found between maternal disulfide/native thiol (p =.262), maternal disulfide/total thiol (p =.152), maternal native thiol/total thiol (p =.153) rates in both groups. No statistically significant difference was determined between the patients with meconium and the control group in terms of cord blood IMA (p =.474), Albumin levels (p =.664), cord blood Native thiol (p =.944), cord blood total thiol (p =.612) levels and cord blood disulfide/native thiol (p =.240), cord blood disulfide/total thiol (p =.276), cord blood native thiol/total thiol (p =.277) rates. Conclusion: Determination of a decrease in SH and Total Thiol levels in maternal serum and an increase in the meconium group’s IMA level was interpreted as a shift of antioxidant balance toward oxidant in this group.