P0716 - Comparison of placental pathology and placental culture as predictors of clinical sepsis in neonates

Purpose: Chorioamnionitis, the inflammation of fetal membranes due to ascending bacteria from the vagina and cervix, has been shown to be a risk factor for developing neonatal sepsis. The diagnosis of chorioamnionitis relies on clinical findings of maternal fever, maternal and fetal tachycardia, and uterine tenderness. While placental pathology is used to histologically confirm the presence of chorioamnionitis, placental cultures are not currently validated as a method to diagnose chorioamnionitis or assess risk for neonatal sepsis. This study aims to evaluate the correlation of both placental culture and placental pathology with neonatal outcomes and to assess their predictive value in the identification of neonatal sepsis.

Methods: We performed retrospective chart reviews on infants and mothers for whom a placental culture and pathology was sent at Loyola University Medical Center from January 2017 to December 2019. We separated the infants into cohorts based on whether or not they had positive placental cultures and positive placental pathologies suggestive of chorioamnionitis. We then used both linear and logistic regression models adjusting for maternal and infant demographic factors such as age, sex, race, prenatal care, and antibiotic use in order to evaluate the correlations of these factors with infants' length of stay, mortality, and the development of respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), retinopathy of prematurity (ROP), and clinical sepsis during their hospital stay. Clinical sepsis was defined as either having confirmed bacteremia or meeting the neonatal SIRS criteria without the presence of bacteremia. Sensitivity, specificity, and positive and negative predictive values were also calculated.

Results: We reviewed the maternal placental cultures and pathologies for 279 infants. There were 86 infants with neonatal sepsis, a majority of those (89.5%) being clinical sepsis without bacteremia. When controlling for factors that varied between the cohorts, we found that both positive placental cultures and positive placental pathologies were associated with an increased risk of clinical sepsis (OR 4.66, p=0.04; OR 8.09, p=0.001, respectively). Additionally, having a positive placental pathology was associated with an increased length of hospital stay (OR 9.31, p=0.02). When conducting a sensitivity and specificity analysis concerning the development of clinical sepsis, the specificity of placental pathology (57.87%, 95% CI [51.54, 64.02]) was significantly greater than that of placental culture (27.17%, 95% CI [21.79, 33.08]), as was the positive predictive value (15.75%, 95% CI [12.78, 19.25] vs. 10.19%, 95% CI [8.61, 12.04], respectively), whereas sensitivity and negative predictive value were comparable.

Conclusion: This study suggests that both positive placental cultures and positive placental pathologies correlate with the development of neonatal sepsis. Placental pathology is superior to placental culture in predicting the development of neonatal sepsis.