Early postnatal immature-to-total neutrophil ratio in the histological chorioamnionitis among neonatal intensive care unit infants

Abstract

ObjectiveHistological chorioamnionitis (hCAM) is a major risk factor for early-onset sepsis. Predictive methods for hCAM are needed in clinical practice during the early postnatal period. To examine the relationship between hCAM and perinatal variables including early postnatal immature-to-total neutrophil ratio (ITR). Study designA single-center study was undertaken at Ohta Nishinouchi Hospital between April 1, 2016 and June 30, 2023. Blood samples and placenta collected from study candidate infants admitted to the neonatal intensive care unit were assessed by univariate analyses and multivariate logistic regression analysis. We also assessed the test performance of ITR and maternal white blood cell (WBC) counts by area under a receiver operating characteristic (ROC) curves. ResultsA total of 725 infants were analyzed (496 in the non-hCAM group and 229 in the hCAM group). Significant relationships were observed between hCAM and ITR (p < 0.001, odds ratio (OR), 1.067; 95% confidence interval (CI), 1.041 to 1.093). Per the ROC curves, an ITR (%) of 7.15 could predict hCAM at a sensitivity of 55.9% and specificity of 71.9% [area under the curve (AUC) = 0.691, p < 0.001, 95% CI, 0.649 to 0.733]. Further, maternal WBC counts of 9.85 ( × 109/L) predicted hCAM with 69.0% sensitivity and 67.3% specificity (AUC = 0.710, p < 0.001, 95%CI, 0.669 to 0.750). ConclusionsEarly postnatal ITR was high in cases with greater leukocyte invasion into the placenta tissue, which may be a biomarker of the presence and/or severity of hCAM. Histological CAM should be considered when the early neonatal ITR (%) is 7.15 or higher.