[Prenatal diagnosis of nuchal edemas and cystic hygromas of the neck. 49 cases].

OBJECTIVES

Determine the pathogenesis of fetal nuchal oedema and cystic hygromas of the neck and establish prenatal prognosis factors.

METHODS

Retrospective study of 49 cases including 35 early diagnoses (10 to 14 weeks gestation) and 14 late diagnosis (after 15 weeks). Chorial villosity biopsy was performed for fetal karyotype.

RESULTS

The global rate of genetic or chromosomic abnormalities in the fetuses was 47%. The fetuses with nuchal associated with other echographic anomalies had a high risk of chromosomic aberrations (80%). Fetuses with nuchal oedema alone during the first trimester had a higher risk of trisomy 21 proportionally with the age of the mother and paradoxically no trisomy 21 was found in women under 30 years of age. When early nuchal oedema regressed spontaneously in an euploid fetus, echographic surveillance can be proposed to detect possible polymalformation syndromes discovered late. Cystic hygromas of the neck were diagnosed from 15 weeks gestation and were always pathologic.

CONCLUSION

Interpreting nuchal images in the fetus must take into account the echographic term at discovery and its isolated or associated nature. Further studies are needed to determine indications for chorial villosity biopsy in mothers under 30 with a fetus with isolated nuchal oedema which regresses spontaneously during the first trimester.