Neutrophil/Lymphocyte Ratio: Predictive Biomarker for Outcomes of Early Pregnancy of Unknown Location [7L

Abstract

INTRODUCTION: Pregnancy of unknown location (PUL) (positive pregnancy test with no evidence of intrauterine or extrauterine pregnancy on Transvaginal sonogram) requires serial hCG levels and imaging till final location of pregnancy is ascertained. Inflammation plays part in pathogenesis of abnormal pregnancies. Neutrophil/lymphocyte ratio (NL) is a marker of inflammation and prognosis. We conducted the first study to investigate the role of NL as predictor of outcomes of PUL. METHODS: Retrospectively, 145 patients presenting to ER at tertiary care hospital from Jan 2011-Jan 2016 were included, with exclusion criteria of hemodynamic instability, intraperitoneal hemorrhage, underlying cancer or hematological disorder, infection, smoker. Study was IRB exempted. Demographics, parity, presenting symptoms, b-hCG levels and NL ratio at presentation were noted. Patients followed up in time and final outcomes classified as: Definite intrauterine pregnancy, Nonviable pregnancy, definite ectopic pregnancy, probable ectopic, spontaneously resolving PUL, treated persistent PUL. SPSS software was used for statistical analysis. RESULTS: NL for normal versus abnormal pregnancy (all other categories) was 1.868±0.12 vs 3.08±1.81 (P=.001). NL for intrauterine versus extrauterine pregnancies were compared = 2.077±1.11 vs 2.74±0.83 (P=.0058). For hCG levels less than 3500, NL for normal versus abnormal pregnancies were 1.93±0.25 vs 2.92±0.34 (P<.001). NLR > 1.83 had AUC =0.793, sensitivity 86.9%, specificity 62.3% (ROC). Binary regression analysis revealed NLR was statistically significant (beta= 2.83, P=.002). CONCLUSION: NL could triage patients with PUL. Larger studies are needed to confirm the utility of this test which could save multiple labs and imaging, and avoid catastrophes like administration of methotrexate to normal Intrauterine pregnancy.