RecruitingDevice studyFetoscopic Endoluminal Tracheal OcclusionThis is a single site pilot trial to study the feasibility of Fetoscopic Endoluminal Tracheal Occlusion (FETO) therapy in the most severe group of fetuses with congenital diaphragmatic hernia (CDH) at Midwest Fetal Care Center, a collaboration between Allina Health and Children's Minnesota. This procedure aims to increase fetal lung volume before birth and improve survival after birth. This study will enroll 10 pregnant people and their baby who meet study criteria.