Diagnosis and management of early non-immune hydrops fetalis

Fetal hydrops is a common symptom of fetal disease at any stage of gestation. The aetiological mechanisms leading to non-immune fetal hydrops are complex and their impact variable at different stages of gestation. In early pregnancy, primary or secondary intra-uterine cardiac failures due to major cardiovascular defects are more often linked to a chromosomal abnormality than during the second half of gestation. In these cases, an increase of the nuchal translucency thickness is probably the first stage of fetal hydrops. Depending on the severity of the underlying defect, the next stage is generalized skin oedema with eventual placental oedema, ascites and pleural effusion. The natural history of fetal hydrops remains poorly understood and thus the prognostic factors determining fetal outcome are still unknown. Examination of the fetal nuchal anatomy between 10 and 15 weeks of gestation and the follow-up of these pregnancies offer an opportunity for an early screening in most aneuploidies and cardiovascular defects, and a better understanding of the aetiopathology of fetal hydrops.