To investigate whether gestational diabetes mellitus (GDM) was associated with survival without bronchopulmonary dysplasia (BPD) in very preterm infants (VPIs).

Retrospective multicentre cohort study.

A total of 79 neonatal intensive care units across China, January 2019 to December 2021.

A total of 23 752 VPIs (

The primary outcomes are survival without BPD at 36 weeks’ postmenstrual age (PMA) and its components.

Infants exposed to GDM were associated with a higher rate of survival without BPD (aOR 1.12, 95% CI 1.04 to 1.21) at 36 weeks PMA and lower mortality (aOR 0.75, 95% CI 0.64 to 0.84) before 36 weeks PMA than unexposed infants. However, no significant association was observed between GDM and BPD at 36 weeks PMA (aOR 0.94, 95% CI 0.87 to 1.02), respiratory distress syndrome, need for advanced resuscitation or mechanical ventilation. After propensity score matching, GDM-exposed VPIs maintained higher survival without BPD (aOR 1.13, 95% CI 1.02 to 1.26) and lower mortality (aOR 0.81, 95% CI 0.68 to 0.97). These associations were strongest in infants born before 28 weeks (aOR 1.32, 95% CI 1.11 to 1.57) and those small for gestational age (aOR 1.41, 95% CI 1.11 to 1.80).

GDM was not associated with worsened BPD in VPIs. The positive association with survival and survival without BPD warrants could reflect a selection bias.