Fetal pleural effusion Fetal chylothorax 2022-01-22T07:37:48Z The presence of chyle (a type of lipid-rich lymph) in the pleural space (the space surrounding the lung) as observed in a fetus. Fetal chylothorax is associated with a high mortality rate. The most serious consequences of fetal chylothorax are pulmonary hypoplasia, congestive heart failure, and hydrops. It may occur as an isolated disorder or as a feature of diseases such as trisomy 21, Turner syndrome, and Noonan syndrome. Chylous pleural effusion impairs normal development of fetal lungs by pressure effects and can lead to pulmonary hypoplasia, mediastinal shift, and impaired circulation.