Diagnosis and management of primary fetal pleural effusion: A narrative review

Primary fetal pleural effusion involves the accumulation of fluid in the fetal pleural space, posing considerable challenges for perinatal diagnosis and management. Primary effusions, emerging from the maldevelopment of lymphatic vessels, differ significantly from secondary effusions, which are associated with a spectrum of anomalies and conditions, affecting clinical approach and prognosis. The diagnosis of primary fetal pleural effusion is one of exclusion. The natural history of the condition ranges from spontaneous resolution in mild cases to progression to life-threatening complications. Fetal interventional strategies, including thoracocentesis, pleurodesis, and thoracoamniotic shunt placement, have evolved with varying degrees of success. The prognosis is largely affected by gestational age at diagnosis, the presence of hydrops, and the implementation of fetal intervention, with improved outcomes observed in non-hydropic fetuses. This narrative review focuses on primary fetal pleural effusion, detailing its diagnosis, natural history, management options, and outcomes, with the aim of clarifying the best approaches to improve outcomes for affected fetuses.