Postnatal resolution of non-chylous primary fetal hydrothorax

We describe two cases of non-chylous primary fetal hydrothorax not associated with hydrops or associated malformations. Repeated ultrasonographic examinations, to detect development of hydrops or progression of intrapleural effusion, were used to evaluate the need for intrauterine thoracocentesis and to decide the optimal time for delivery. Both infants did well after postnatal evacuation of the intrapleural fluid. Pre- and postnatal investigation to find the pathophysiological mechanism leading to hydrothorax were negative. We conclude, in agreement with previous work, that primary fetal hydrothorax is generally associated with a favourable outcome.