Objective: The study aims to investigate maternal serum thiol/disulfide homeostasis and ischemia-modified albumin (IMA) levels of women who were submerged during labor. Material and methods: Sixty-four pregnant women were enrolled in this study. Thirty-four women were submerged during the first stage of labor and 30 women were not. Native thiol, total thiol, disulfide, albumin, IMA, disulfide/native thiol, disulfide/total thiol and native thiol/total thiol concentrations were measured and demographic data were obtained. Results: Cord blood pH, serum disulfide levels and (disulfide/total thiol) x 100 levels were significantly lower in the water immersion group (P < 0.01, P = 0.01 and P < 0.01, respectively). Native thiol, total thiol, albumin and IMA levels were higher in the water immersion group P < 0.01, P < 0.01, P = 0.001 and P < 0.01, respectively). Conclusion: Water immersion during the first stage of labor was found to be associated with deterioration of thiol-disulfide homeostasis with respect to antioxidant status while IMA levels were higher, suggesting an ischemic condition.