Introduction Untreated, fetal hydrothorax is associated with significant morbidity and a mortality rate of approximately 80–90%.

Population 114 fetuses with isolated large pleural effusions underwent pleuroamniotic shunting at our perinatal centre. All had an extensive antenatal work-up including: detailed anatomy, echocardiogram, karyotype, infectious testing for CMV, Toxoplasmosis and Parvovirus. 84 were bilateral, 72 (63%) were hydropic and 41 (36%) had associated polyhydramnios,. Mean maternal age was 30.2 years, the mean gestation at diagnosis was 25 weeks and at shunting 27.6 weeks. 64 required bilateral shunts and, of unilateral, 27 were left-sided and 23 right-sided. 25 underwent simultaneous amnioreduction. The mean interval to delivery was 7 wks.

Results There were 15 (12.3%) intrauterine deaths. 26 (23%) neonatal deaths and 73 (64.7%) survivors. Additional abnormalities including genetic, metabolic and neurological syndromes were identified antenatally in 8 cases and postnatally in 9. Of 99 liveborn babies, 76 (77%) delivered at our perinatal centre. Postnatally, 46 required ventilation, 38 (50%) required chest tubes, of whom 19 (26%) died. Of 73 survivors, 2 (3%) were lost to follow-up, 4 (5.5%) are < 4 months of age, 10 (14%) showed evidence of significant developmental delay, including 3 with Trisomy 21, and 1 had mild developmental delay. Fifty five (75%) are developing normally.

Conclusion Fetal hydrothorax can be associated with a wide range of conditions, some of which may not be detectable antenatally. Fetal therapy significantly improves perinatal outcome, although mortality remains high. On long term follow up, approximately 75% of survivors are developmentally normal.