Isolated pleural effusion is an uncommon fetal condition characterized by fluid accumulation in the pleural cavity. It may occur independently or as part of hydrops fetalis.

A 26-year-old primigravida at 20 weeks of gestation was referred for fetal left-sided pleural effusion. Amniocentesis confirmed normal chromosomes and thoracocentesis affirmed chylothorax. Despite thoracocentesis, recurrent effusion necessitated thoracoamniotic shunt (TAS) placement at 26 weeks. At 30 weeks, there was preterm prelabor rupture of membranes which was conservatively managed until suspected chorioamnionitis necessitated an emergency cesarean section.

The primary concern with fetal pleural effusion is lung compression, leading to pulmonary hypoplasia, and potential progression to hydrops. Prenatal diagnosis involves ultrasonography and may include thoracocentesis for cytology and amniocentesis for chromosomal analysis. Management options range from conservative monitoring to invasive procedures like thoracocentesis or thoracoamniotic shunt placement, depending on the severity and gestational age.

This case underscores the need for timely intervention in managing fetal pleural effusion for optimal maternal and fetal outcomes.