RecruitingDevice studyFetoscopic Endoluminal Tracheal OcclusionThe purpose of this research study is to see if the FETO surgery and FETO release (surgery to remove the device) works and is safe for babies with severe right or left Congenital Diaphragmatic Hernia (CDH). CDH is a condition in which a hole in the baby's diaphragm allows the abdominal organs to move into the chest and limit lung growth. The goal of the FETO device is to block the airway with a balloon-type device, allowing fluid to build up and help the unborn baby's lungs grow. Bigger lungs may improve the baby's quality of life.