Background Early Onset Neonatal Sepsis (EONS) is one of the commonest and serious problem for newborn babies, incidence in India being 38 per 1000 intramural live births. Currently EONS diagnosis is mainly considered on maternal risk factors and non-specific neonatal symptoms. Also, initiating emperical antibiotics in timely fashion is critical in decreasing morbidity and mortality. But since a gold standard test is unavailable for EONS especially in the initial hours of life, number of neonates who require antibiotics is high. This inturn results in increase in disadvantages related to the antibiotic use and prolonged hospital stay.

We tried to explore whether placental histology can be used as an additional tool in diagnosing EONS thereby avoid the unnecessary antibiotic usage and hospital stay for neonates.

Objectives To determine whether placental histology has good correlation with probable or proven early-onset neonatal sepsis (EONS), thereby help to diagnose EONS and guide in clinical decision-making.

Methods This retrospective observational study comprised 101 newborn babies, both term and preterm, who were admitted to the neonatal intensive care unit of Rajagiri Hospital, Aluva, Kochi, Kerala, India between June 2017 and June 2020. EONS was defined as maternal risk factors with clinical symptoms (Suspected EONS) plus raised serial C-reactive protein (CRP) >10 mg/L and a positive (Proven EONS) or a negative (Probable EONS) blood culture. Placentae were studied for a histological inflammatory response and scored according to the Amniotic Fluid Infection Nosology Committee of Perinatal Section, the Society for Pediatric Pathology, and reported by Redline et al. in 2003.

Results Chorioamnionitis was seen in 42/101(41.6%) placentae and this occurred significantly more often in newborn babies with probable or proven EONS (p < 0.05). No features of chorioamnionitis were seen in 51/61(83.6%) of newborn babies with suspected EONS (p<0.05).

Conclusions Histological examination of the placenta for acute chorioamnionitis has statistically significant correlation with probable and proven EONS and can be a potential tool to guide clinical decision-making and thereby antibiotic use if report is made available within 24 hours as in frozen section study.