A Comparison of the Incidence of Neonatal Morbidities Using Various Criteria for Histologic Chorioamnionitis in Very Low Birth Weight Infants

Abstract

Background: Although there have been many studies supporting the adverse effects of histologic chorioamnionitis (HC) on neonatal outcomes, debates continue on this issue. Objectives: To determine the relationship between HC and neonatal morbidities in very low birth weight (VLBW) infants using criteria reflecting the extent and site of inflammation. Methods : We performed a retrospective cohort study of 261 VLBW infants who were admitted to a single tertiary academic center between 2008 and 2012. Based on the site within the placenta and the extent of neutrophil infiltration, four criteria for HC were developed that reflected the severity of the inflammatory process and the site of inflammation. We compared the incidence of neonatal morbidities in VLBW infants with and without HC using different HC criteria. Results: The gestational age (GA) was significantly lower for the HC-exposed group compared to the unexposed group. The birth weight and sex ratio were not different. The incidence of BPD was higher in the HC-exposed infants based on criterion 2. HC was significantly associated with severe ROP (≥stage 3) and the need for laser surgery, based on criteria 1 and 3. However, the relationship disappeared upon further analysis after adjusting for GA and birth weight. On the other major morbidities, we did not observe an independent relationship with HC either except respiratory distress syndrome (RDS) which showed a decreased incidence among the HC-exposed infants, based on all of the criteria. Conclusions: The results of this study indicate that HC significantly decreases the risk of RDS but has no associations with other morbidities.