Bronchopulmonary dysplasia and postnatal growth following extremely preterm birth

Objectives: To report the current incidence of bronchopulmonary dysplasia (BPD) and to compare changes in weight and head circumference in infants who developed BPD compared to the infants who did not develop BPD. Design: Retrospective whole-population study. Setting: All neonatal units in England between 2014 and 2018. Patients: All liveborn infants born <28 completed weeks of gestation. Interventions: The change in weight z-score (ΔWz) was calculated by subtracting the birth weight z-score from the weight z-score at 36 weeks postmenstrual age (PMA) and at discharge and the change in head circumference z-score (ΔHz) was calculated by subtracting the birth head circumference z-score from the head circumference z-score at discharge. Main outcome measure: BPD was defined as the need for any respiratory support at 36 weeks PMA. Results: Eleven thousand, eight hundred and six infants were included in the analysis. The incidence of BPD was 57.5%; 18.9% of the infants died before 36 weeks PMA. The median (IQR) ΔWz from birth to 36 weeks PMA was significantly smaller in infants that developed BPD [-0∙69 (-1∙28 to -0∙14), N=6,105] than in those who did not develop BPD [-0∙89 (-1∙40 to -0∙33), N=2,390, adjusted p<0∙001]. The median (IQR) ΔHz from birth to discharge was significantly smaller in infants that developed BPD [-0∙33 (-1∙69 to 0∙71)] than in those who did not develop BPD [-0∙61 (-1∙85 to 0∙35), adjusted p<0∙001]. Conclusions: Postnatal growth was better in infants diagnosed with BPD compared to infants without BPD possibly because of more aggressive nutrition strategies.