Is there a relationship between early pregnancy loss and maternal serum human X-box binding protein 1 level?

The human X-box binding protein 1 is a transcription factor that is expressed by cellular oxidative stress. We aimed to analyze the relationship between early pregnancy loss and maternal blood X-box binding protein 1 levels. Patients who presented to our Obstetrics and Gynecology clinic between October 2019 and February 2020 were included in this study. Patients were divided into two groups: Group 1 included healthy pregnant women and Group 2 included patients who were diagnosed with missed abortion. First, blood samples were taken from the patients in group 2 when they were diagnosed with missed abortion. While evaluating the patients in group 1, the average gestational weeks of the patients in group 1 were calculated and blood samples were taken between the same weeks. Next, patients with healthy pregnancy in group 1 were followed up prospectively and double screening test were performed at the perinatology outpatient clinic at the end of the 1st trimester, and the blood results of the patients with normal results were evaluated. Blood samples extracted from these patients were centrifuged at -80 °C and stored until analyses. Serum X-box binding protein 1 levels were measured using enzyme-linked immunosorbent assay kits (Cusabio, Wuhan, China). Eighty-five patients were included in this study: 42 in Group 1 and 43 in Group 2. There was no difference between the groups in terms of age, body mass index, ethnicity, and systemic illness. Serum X-box binding protein 1 levels were significantly higher in Group 2 (129.89 ± 7.58 ng/L) than in Group 1 (119.56 ± 5.99 ng/L) (p < 0.001). Serum X-box binding protein 1 levels higher than the cut-off value of 119.05 ng/L were associated with a higher risk of early pregnancy loss. Serum X-box binding protein 1 levels may be used to predict early pregnancy loss; however, additional comparative studies are required to confirm this result.