Journal of Ultrasound in Medicine, Vol 14, Issue 8 565-568, Copyright © 1995 by American Institute of Ultrasound in Medicine
Nuchal translucency thickness and crown-rump length in twin pregnancies with chromosomally abnormal fetuses
P. P. Pandya, F. Hilbert, R. J. Snijders and K. H. Nicolaides
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London, United Kingdom.
We retrospectively examined the crown-rump length and nuchal translucency
thickness of each fetus in eight twin pregnancies in which karyotyping at
10 to 14 weeks' gestation demonstrated that at least one of the fetuses was
chromosomally abnormal. Eight fetuses had trisomy 21 and two had trisomy
18. The nuchal translucency thickness was more than 2.5 mm in nine (90%) of
the trisomic fetuses and in one of the chromosomally normal ones. In
contrast, the crown-rump length was below the fifth percentile in only one
of the fetuses with trisomy 18; all other measurements were within the
normal range.