© 2022, Yuzuncu Yil Universitesi Tip Fakultesi. All rights reserved.This study aims to evaluate the effectiveness of PCT (Platelet crit), NLR (Neutrophil-to-lymphocyte ratio), and PMI (Platelet Mass Index), which are among the complete blood count parameters, in predicting missed abortion (MA). The case-control study was conducted between January 1, 2020, and January 2022. A total of 926 pregnant women, including 474 MA and 452 normal patients, were included in the study. There were no significant differences between the patient and control groups in terms of age, gestational week, body mass index (BMI), gravida and parity, and thyroid functions (p>0.05). PMI, PCT, and NLR values were significantly higher in the MA group (p<0.05). While there was a strong positive relationship between PMI and PCT, there was a negative relationship between PMI and NLR (p<0.05). In the ROC anal ysis, PCT>0.24, NLR>2.99, and PMI>2430.9 were significantly associated with an increased risk of missed abortion (P<0.05). Logistic regression analysis rev ealed that a one-unit increase in PCT resulted in a statistically significant 3.41-fold increase in the risk of missed abortion, a one-unit increase in NLR resulted in a 2.56-fold increase, and a one-unit increase in PMI resulted in a 1.004-fold increase (p< 0.05). We think that PMI, NLR, and PCT values obtained from complete blood count parameters are important predictors of missed abortion.