In this study, we determined the outcome in cases of isolated nuchal lucency seen
sonographically in the first trimester in fetuses without karyotypic abnormalities. We
reviewed all cases of isolated localized fetal nuchal lucency (3 mm or greater) in 9 to 14
week fetuses over a 4 year period. Fetuses with additional sonographic abnormalities were
excluded. The width of the nuchal lucency at initial sonogram as well as findings on
subsequent scans were tabulated. Karyotypic, pathologic, and clinical follow‐up data were …

Chromosomal anomalies occur very frequently in fetuses exhibiting diffuse nuchal fluid and
generalized hydrops, and a poor outcome may be expected. A localized nuchal lucency is,
however, consistent with a normal condition at birth. How karyotypically normal fetuses with
a localized nuchal lucency fare after the first trimester remains uncertain. This study included
41 fetuses initially 9 to 14 weeks of gestational age, seen in a 4-year period, who had a
localized nuchal lucency measuring at least 3 mm transversely. Ultrasonography used both …