Intrauterine Ureaplasma is associated with small airway obstruction in extremely preterm infants

Background The long‐term follow‐up of lung function (LF) in extremely preterm (EP) infants with bronchopulmonary dysplasia (BPD) has shown a worldwide increase in small airway obstructions (SAO). Objectives We investigated the relationships between intrauterine Ureplasma infection in EP infants and bubbly/cystic lung, BPD, and SAO at school age. Methods Placental pathology, placental Ureaplasma DNA (pU‐DNA), and cord blood immunoglobulin M (IgM) (C‐IgM) were investigated in 360 EP infants born from 1981 to 2004. Maternal amniotic inflammatory response (M‐AIR) scores and hemosiderin deposition (HD) were estimated in the chorioamnion. The study subjects were divided into groups based on their M‐AIR scores. Their LF at school age was compared with those of 33 healthy siblings. Findings pU‐DNA and C‐IgM were significantly related to SAO at school age (p 1000 units had an odds ratio (OR) of 35 (95% confidence interval: 10–172) and 18 (5.6–67) for bubbly/cystic lung, and 11 (3.1 − 43) and 31 (4.5–349) for severe BPD, and 5.3 (2.1–11) and 12 (2.4–74) for SAO, respectively. The ORs of surfactant treatment, BPD grade III, O2 at 40 weeks, HD, and C‐IgM >30 mg/dl for SAO were 0.21 (0.075–0.58), 5.3 (2.1–15), 2.5 (1.4–4.6), 3.6 (1.5–9.1) and 2.5 (1.0–5.2). 84% (90/107) SAO infants showed no or mild BPD in infancy, and 61% of infants had no severe CAM. Conclusion Our long‐term cohort study of LF in EP infants revealed that intrauterine Ureaplasma was associated with bubbly/cystic lung, severe BPD, and SAO at school age.