OP10.02: The influence of body mass index on first trimester fetal growth

Abstract

Aim: Pulmonary hypoplasia and hypertension (PHT) are key problems of newborns with isolated congenital diaphragmatic hernia (CDH). Lung size to head ratio (O/E LHR) and liver position are related to the degree of pulmonary hypoplasia. Prenatal evaluation of the lung vasculature can be either through anatomical measurements, flow patterns, or by measuring vascular reactivity. We evaluated the course and predictive value of the fetal pulmonary artery reactivity to maternal hyperoxygenation (HPVR) in selected fetuses with severe CDH prior to and following fetoscopic endoluminal tracheal occlusion (FETO). Methods: 38 fetuses underwent FETO around 28 wks and the balloon was removed at 34 weeks. We performed a HPVR test and measured O/E LHR within 2 days before (T1,T3) and after (T2,T4) each procedure. Outcomes included neonatal survival, occurrence of PHT unresponsive to inhaled-NO (iNO). Results: The HPVR-test and O/E LHR follow different courses around the time of FETO. They are best predictive when HPVR is measured following balloon removal (T4; p<0.002). Fetuses who survive have a larger increase in O/E LHR and decrease of resistance in the first branch of the main pulmonary artery than those who died. Both are also predictive of PHT unresponsive to iNO. Discriminant analysis confirms that the LHR and HPVR independently predict outcome. Conclusions: In fetuses undergoing FETO pulmonary vascular reactivity to oxygen and lung size are independent predictors of neonatal survival and pulmonary hypertension. The hyperoxygenation test merits further study in expectantly managed cases.