Statistical analyses
Descriptive statistics was compiled, tabulated and presented as absolute numbers with means or medians and corresponding standard deviation or interquartile range, depending on covariate distribution. To assess the impact of clinical and laboratory characteristics of deliveries complicated by chorioamnionitis the cohort was - for this specific question - treated as a case-control study, where the specific characteristics of chorioamnionitis was the exposure and composite adverse neonatal outcome was the outcome. Logistic regression models were used to estimate odds ratios (ORs) of the association between each exposure and risk of neonatal outcomes. Inflammatory laboratory measurements were categorized into tertiles, with the lowest tertile used as a reference. A multivariate model adjusted for maternal age at delivery, smoking status, BMI and parity. All analyses were performed using SASĀ® Software (Statistical Analysis Software version 9.4, SAS Institute Inc, Cary, North Carolina, USA).