The Role of Eosinophil Count and Eosinophil-Based Complete Blood Cell Indices in Predicting the Risk of Tubal Ectopic Pregnancy Rupture

<b>Aims/Background</b> Patients with an ectopic pregnancy (EP) may become hemodynamically unstable if there is rupture and bleeding in the structure in which the pregnancy is implanted (usually the fallopian tube). Rupture should be suspected in patients with a sudden onset of severe and persistent abdominal or pelvic pain, or symptoms or signs suggestive of hemodynamic compromise (e.g., hypotension, tachycardia). This study investigated the utility of maternal serum eosinophil count and eosinophil-based complete blood cell indices in determining the risk of rupture of tubal ectopic pregnancies. <b>Methods</b> This retrospective study included a patient group (n = 41) diagnosed with ruptured EP and a control group (n = 60) diagnosed with tubal EP between January 2020 and December 2024 at Afyonkarahisar Health Sciences University. Hemogram results of both groups during hospitalization were examined. The utility of eosinophil count, eosinophil to lymphocyte ratio (ELR) (eosinophil/lymphocyte), neutrophil to eosinophil ratio (NER) (neutrophil/eosinophil), leukocyte to eosinophil ratio (LER) (leukocyte/eosinophil), and eosinophil to monocyte ratio (EMR) (eosinophil/monocyte) in the prediction of EP rupture were evaluated. <b>Results</b> The ruptured EP group complication had significantly higher NER and LER values compared to the control EP group (<i>p</i> < 0.05). The optimum cutoff values for NER and LER were 47.86 (Area Under the Curve (AUC): 0.65, 95% CI: 0.54-0.76, 65.9% sensitivity, 63.7% specificity, <i>p</i> = 0.012) and 129.16 (AUC: 0.72, 95% CI: 0.62-0.82, sensitivity 58.5% and specificity 66.7%, <i>p</i> < 0.001), respectively. The eosinophil count and EMR values were lower in the ruptured EP group (<i>p</i> < 0.05). The optimum cutoff values for eosinophils and EMR were 0.095 × 10⁹/L (AUC: 0.62, 95% CI: 0.50-0.73, sensitivity 56% and specificity 57%, <i>p</i> = 0.04) and 0.16 (AUC: 0.65, 95% CI: 0.54-0.76, sensitivity 59% and specificity 62%, <i>p</i> = 0.013), respectively. <b>Conclusion</b> Eosinophil count, EMR, NER, and LER can be used as potential markers to predict the development of EP rupture with relatively low sensitivity and specificity. However, further studies are needed to clarify the role of eosinophil count, EMR, NER, and LER in predicting rupture.