Supplementary Material for: Three-dimensional Ultrasound Evaluation of Lung Volume in Fetuses with Abdominal Wall Defect

Introduction: Abdominal wall defects (AWD) interfere with postnatal respiratory parameters. We aimed to evaluate lung volume (LV) in fetuses with AWD using three-dimensional (3D) ultrasound (US) and to correlate AWD with the type (omphalocele and gastroschisis) and size of the defect and neonatal morbidity and mortality. Methods: This prospective study included 72 pregnant women with fetuses with AWD and a gestational age <25 weeks. Abdominal volume, 3D US LV, and herniated volume were acquired every 4 weeks up to 33 weeks. LV was compared with normal reference curves and correlated with abdominal and herniated volumes. Results: Omphalocele (p<0.001) and gastroschisis (p<0.001) fetuses had smaller LV than did normal fetuses. LV was positively correlated with abdominal volume (omphalocele, r=0.86; gastroschisis, r=0.88), whereas LV was negatively correlated with omphalocele-herniated volume/abdominal volume (p<0.001, r= -0.51). LV was smaller in omphalocele fetuses that died (p=0.002), were intubated (p=0.02), or had secondary closure (p<0.001). In gastroschisis, a smaller LV was observed in fetuses discharged using oxygen (p=0.002). Discussion/Conclusion: Fetuses with AWD had smaller 3D LV than normal fetuses. Fetal abdominal volume was inversely correlated with LV. In omphalocele fetuses, a smaller LV was associated with neonatal mortality and morbidity.