Oxidative stress has been identified to play a vital role in the pathogenesis of spontaneous abortion were characterized as an imbalance between the generation of pro-oxidants, free radicals, and reactive species, and enzymatic and non-enzymatic antioxidant defenses in favor of the former. In the present study, the pro-oxidant-antioxidant balance was assessed in women with spontaneous abortion and compared with healthy age-matched controls. A group of 50 females with spontaneous abortion were considered patients, and a group of age-matched healthy pregnant women was considered controls. The pro-oxidant-antioxidant balance (PAB) assay was carried out on participants' serum samples. The mean age of the spontaneous abortion group was 30.84 ± 3.82, and controls were 26.53 ± 4.05 years. The obtained PAB values were 236.74 ± 11.37 HK and 148.69 ± 76.50 HK in patients and controls. Our results demonstrate the significant rise of PAB values in subjects with spontaneous abortion compared to healthy controls (p< 0.0001). Our study showed that the PAB values might be involved in the termination of spontaneous abortion.