Duration of Systemic Inflammation in the First Postnatal Month Among Infants Born Before the 28th Week of Gestation.

Extremely low gestational age newborns (ELGANs, <28 completed weeks of gestation) that exhibit fetal and neonatal systemic inflammatory responses are at increased risk for developmental adversity, especially if the inflammatory process is sustained. We evaluated pro-inflammatory cytokine patterns in whole blood of 1220 ELGANs on one or more of postnatal days 1, 7, 14, 21, and 28. Protein concentrations were divided into quartiles within gestational week categories. We calculated odds ratios (OR) with 99% confidence intervals (CI) for having a concentration in the top quartile for each protein given that the infant had a protein concentration in the top quartile 1 week or more earlier compared to infants who did not. ELGANs who have elevated systemic levels of IL-6R, TNF-α, or RANTES on their first postnatal day are approximately twice as likely to have elevated levels of these cytokines at the end of each of the first postnatal month. In some, this twofold risk increase persisted for the entire first postnatal month. In extremely preterm newborns, inflammatory processes can be sustained over weeks.