Objectives: To report the current incidence of bronchopulmonary dysplasia (BPD) and to compare changes in weight and head circumference between infants who developed BPD and infants who did not.

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 birthweight z-score from the weight z-score at 36 weeks postmenstrual age (PMA) and at discharge. 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: 11 806 infants were included in the analysis. The incidence of BPD was 57.5%, and 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 who developed BPD (-0.69 (-1.28 to -0.14), n=6105) than in those who did not develop BPD (-0.89 (-1.40 to -0.33), n=2390; adjusted p<0.001). The median (IQR) ΔHz from birth to discharge was significantly smaller in infants who 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 with infants without BPD possibly due to more aggressive nutrition strategies.