Fetal nuchal oedema: associated malformations and chromosomal defects.

During an 8-year period, oedema in the dorsal cervical region that produces a characteristic tremor on ballotement of the fetal head (nuchal oedema) was observed in 145 (7%) of the 2,086 fetuses that underwent karyotyping in our unit because of fetal malformations and/or growth retardation. Nuchal oedema was distinguished from nuchal cystic hygromata and from hydrops foetalis. In 132 (91%) of the cases with nuchal oedema, there were other fetal malformations, and 53 (37%) fetuses had chromosomal abnormalities, mainly trisomy 21 but also other trisomies, deletions or translocations, triploidy and Turner syndrome. Furthermore, the chromosomally normal fetuses with nuchal oedema had a very poor prognosis because, in many cases, there was an underlying skeletal dysplasia, a genetic syndrome or cardiac defect.