Predicting miscarriage using systemic immune‐inflammation index

To evaluate the clinical significance of the systemic immune-inflammation index (SII) for patients who had miscarriages.The retrospective study included 709 pregnant women who had a miscarriage (nonviable intrauterine pregnancy up to 20 weeks of gestation) and 676 women who carried a viable intrauterine pregnancy up to 20 weeks of gestation-serving as the control group. The study and the control group were compared in terms of demographic characteristics, laboratory test results, and SII values. Furthermore, laboratory test results and SII values were compared between patients in the study group and the control group with a history of genital bleeding (threatened abortion).The mean gestational week of pregnancy was 9.5 ± 3 for the control group and 8.3 ± 2.5 for the study group (p = 0.150). The SII values were higher in the study group than in the control group (p = 0.030). In all participants with a clinical history of genital bleeding, the leukocyte count, neutrophil count, neutrophil-to-lymphocyte ratio (NLR), and SII values were higher in the miscarriage group than the group with viable fetus (p = 0.031, p = 0.003, p = 0.002, p < 0.001). Based on a receiver operating characteristic (ROC) curve analysis, the SII cutoff value for miscarriage was 883.95 (109 /L) (62.6% sensitivity, 62% specificity) in patients with a clinical history of threatened abortion.High SII values in early pregnancy may be used as an additional marker for the prediction of miscarriage, in pregnant women with threatened abortion. Further prediction models including maternal risk factors and multiple markers may be more valuable for clinical practice.