Is the ultrasound definition of fluid collections in non-immune hydrops fetalis helpful in defining the underlying cause or predicting outcome?

The ultrasound findings in 132 patients with non-immune hydrops referred for echocardiographic assessment were retrospectively reviewed. Structural assessment was combined with evaluation of pleural and pericardial effusions, ascites and skin edema. Patients were divided into groups based on the underlying etiology of hydrops. Seventy patients were found to have cardiac abnormalities, including 45 with structural heart disease. Other causes included. chromosomal anomalies, infection, extra-cardiac anomalies, genetic syndromes and, in 40 patients, unknown cause. Analysis of patterns of fluid accumulation revealed a significantly decreased incidence of pleural effusions and ascites in fetuses with an underlying cardiac abnormality. Cardiomegaly based on the cardio-thoracic ratio was significantly more frequent in the cardiac group. When patients were grouped by outcome, no pattern of fluid distribution was found to be characteristic for survival or death. We conclude that ultrasound definition of fluid collections in non-immune hydrops may be helpful in predicting the underlying cause of the hydrops, although there are no specific patterns predictive of outcome.