FIRST-TRIMESTER NUCHAL EDEMA AS A MARKER OF ANEUPLOIDY

Targeted ultrasonographic screening for nuchal fluid accumulation duri ng the first trimester (9-13 weeks) seems to be a recommendable method for the detection of Down's syndrome and other chromosomal anomalies in pregnant women. It compares favorably with current methods of mater nal serum screening performed during the second trimester. Using a 4-m m cut-off value, the detection rate of aneuploidy among our population was found to be 57.1% with a false-positive rate of 0.7% and a positi ve predictive value of 72.7%. Chromosomal analysis should be considere d for fetuses with nuchal translucency equal to or greater than 4 mm i n the first trimester.