Doctor: Héloïse Torchin
Title: Early determinants of bronchopulmonary dysplasia in very preterm infants
Supervisor: Pierre-Yves Ancel
Doctoral school: ED 393 Epidemiology and Biomedical Information Sciences, Université Paris Cité
Date of thesis defense: 07/2018
Jury: Pierre-Yves Ancel, Pierre-Henri Jarreau, Michael John Fayon, Valérie Briand, Géraldine Gascoin-Lachambre, Véronique Houfflin-Debarge
Bronchopulmonary dysplasia (BPD), due to disrupted development of the immature lungs, remains a common respiratory morbidity of very preterm birth. Our aim was to study antenatal and postnatal factors possibly associated with BPD at 36 weeks postmenstrual age, about which epidemiological results have been inconsistent. Data from the EPIPAGE-2 cohort study were used. We first studied the associations between placenta-mediated pregnancy complications and BPD. Pregnancies complicated by fetal growth restriction (FGR) were at higher odds of moderate to severe BPD, whereas hypertensive disorders of pregnancy without FGR were not. We then analyzed the impact of antenatal inflammation, defined using histological chorioamnionitis diagnosis. Among very preterm infants born after spontaneous preterm labor with intact membranes or after preterm premature rupture of the membranes, histological chorioamnionitis was not associated with moderate or severe BPD. Lastly, we found wide inter-center variability in care delivered to preterm infants from their very first days. However, we were not able to explain variations of BPD frequency between centers by these differences of care. Our results concerning the associations between two frequent pregnancy complications and BPD are in part contrary to current pathophysiological models. Understanding early BPD risk factors may help to better define patients for inclusion in clinical trials aiming to decrease BPD rates or severity and to improve clinicians and families knowledge about respiratory morbidity of preterm birth.