Preeclampsia and risk of developing bronchopulmonary dysplasia in very preterm neonates

Introduction: Bronchopulmonary dysplasia (BPD) is still a serious and common complication of prematurity and significantly associated with respiratory morbidity in later life. More insight in true associations is of major importance and can lead to earlier detection and possibly better preventive measurements. It's been hypothesized that both BPD and pre-eclampsia (PE) are associated with dysregulation of angiogenesis and that offsprings of mothers with PE are at risk for developing BPD. However, results of several epidemiological studies are inconclusive. This can probably, at least partly, be explained by adjusting outcome data for intermediates rather than for confounders alone. We assessed if PE is an independent risk factor for development of BPD in very preterm neonates. Materials and methods: We performed an observational cohort study of infants born between 24+0 and 31+6 weeks of gestation (n=308). BPD was diagnosed at 36+0 weeks postmenstrual age (pma) and defined as the need for oxygen (FiO2>0.21) for at least 12 hours per day, for more than 28 days before or at 36+0 weeks pma, and subdivided in mild, moderate or severe by strict criteria applied with an oxygen reduction test. We performed association analysis with univariate and multivariate logistic regression. Clinical cases and summary results: After applying our exclusion criteria we report our primary outcome on 247 neonates. development of bpd occurred in 23.9% (n=59) of which 10.9% (n=27) was moderate to severe. we did find significant evidence that PE is associated with bpd, adjusted odds ratio, 95% confidence interval 4.12 (1.61-10.56). However, after adjusting for additional intermediates there were no statistical significant associations anymore. this shows that correctly recognizing true confounders instead of intermediates (which are part of the causal pathway) is of great importance in identifying true associations. Conclusion: This study shows that PE is an independent risk factor for development of BPD, however the pathogenesis of BPD in offsprings of mothers with PE has to be elucidated in the future. (Table Presented).