Background: Bronchopulmonary dysplasia (BPD) is generally considered to be more frequent in males than in females. We conducted a Bayesian model-averaged (BMA) meta-analysis of studies addressing sex differences in the risk of developing different severities of BPD and BPD-associated pulmonary hypertension (BPD-PH). Methods: We used BMA to calculate Bayes factors (BFs). The BF10 is the ratio of the probability of the data under the alternative hypothesis (presence of sex differences) over the probability of the data under the null hypothesis (absence of sex differences). BPD was classified as BPD28 (supplemental oxygen at or during 28 days), BPD36 (oxygen at 36 weeks postmenstrual age), mild, moderate, and severe BPD. Results: We included 222 studies (541,826 infants). The BMA analysis showed extreme evidence in favor of a male disadvantage in BPD28 (BF10>105), BPD36 (BF10>1021), and severe BPD (BF10=87.55), but not in mild BPD (BF10=0.28), or BPD-PH (BF10=0.54). The evidence for a male disadvantage in BPD decreased as the gestational age of the cohort decreased. Conclusions: We confirmed the presence of a male disadvantage in moderate-to-severe BPD, but not in less severe forms of BPD or in BPD-PH. The male disadvantage in BPD is much less apparent in the more immature infants.

The authors have declared no competing interest.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present work are contained in the manuscript