Congenital chylothorax is a rare but significant neonatal entity with major morbidity and mortality. The study aims to describe the related associations, management and outcomes of this condition in neonates.

This is a retrospective case series of all cases of congenital chylothorax admitted to a tertiary neonatal centre in the last 15 years.

Ten cases of congenital chylothorax were identified. Eight infants were diagnosed antenatally and three infants had antenatal pleural drainage. Most infants were ventilated at birth and required immediate pleurocentesis. Post‐natal management included drainage of fluid, ventilation, albumin replacement, octreotide and dietary modification with medium‐chain triglyceride‐enriched formula. Five infants had chromosomal aberrations identified, while a further two had dysmorphic features not substantiated with routine genetic testing. Noonan's syndrome was the single most common underlying genetic diagnosis. Associated anomalies and malformations were present in 80% of the cohort. There were two deaths in the series, both in infants with multiple co‐morbidities.

Congenital chylothorax is a rare condition with overall prevalence of less than a case per year in our experience. Majority of infants had associated chromosomal anomalies and significant co‐morbidities needing prolonged intensive care.