Morbidity and Mortality in Newborns Exposed to Maternal Chorioamnionitis: An Update

Chorioamnionitis (CA) is a common complication of pregnancy associated with significant maternal, perinatal, and long-term adverse outcomes. Adverse maternal outcomes include postpartum infections and sepsis while adverse infant outcomes include stillbirth, premature birth, neonatal sepsis, chronic lung disease and brain injury leading to cerebral palsy and other neurodevelopmental disabilities. CA is a term commonly used to refer to different clinical or pathological conditions characterized by an infectious and/or inflammatory process that affects primarily the chorioamniotic membranes, but also the amniotic fluid (AF), vessels of the chorionic plate and, eventually, the umbilical cord (funisitis) and the foetus. Its incidence is higher at lower gestational ages (GA), and the main mechanism is believed to be the ascending bacterial infection from the maternal genital tract, even with intact membranes. The inflammatory complications associated with chorioamnionitis have been well described, and these effects may last into adulthood. It diagnosis can be based on clinical criteria, amniotic fluid biochemical or microbiological examination, or by histopathological study of the placenta. CA is an important cause of stillbirth, premature rupture of membranes (PROM), preterm delivery and adverse maternal and neonatal outcomes such as early-onset neonatal sepsis (EONS) and necrotizing enterocolitis (NEC). Its causal association to other neonatal morbidities is controversial. Comparison of studies is challenging due to heterogeneity in diagnostic criteria and morbidity definitions, and results are inconsistent. Additionally, the process's duration and intensity are typically ignored. For all of these reasons, it is challenging to establish evidence-based recommendations for the management of the mother and baby in these situations, and clinical practise varies greatly.