Increased nuchal translucency with normal karyotype

Prevalence and perinatal outcome of dichorionic and monochorionic twins with nuchal translucency above the 99th percentile and normal karyotype

“…However, in monochorionic twins, increased NT may also be produced by hemodynamic imbalances between the fetuses through the vascular anastomoses, which may result in severe early onset of TTTS 3,4 . Previous studies in singleton pregnancies have reported that an increased NT in a fetus with normal karyotype was associated with a poor pregnancy outcome, the chances of which increased exponentially with increasing NT thickness, from 8% when NT ranged between the 95 th and 99 th percentiles to 80-85% when the NT was above 6.5 mm 1,14 . While establishing our reference ranges for NT, we found the 99 th percentile not to be a fixed value, as has been described by other groups 1,15 , but to increase, from 2.27 mm at 45 mm CRL to 3.78 mm at 84 mm 11 .…”

“…Previous studies in singleton pregnancies have reported that an increased NT in a fetus with normal karyotype was associated with a poor pregnancy outcome, the chances of which increased exponentially with increasing NT thickness, from 8% when NT ranged between the 95 th and 99 th percentiles to 80-85% when the NT was above 6.5 mm 1,14 . While establishing our reference ranges for NT, we found the 99 th percentile not to be a fixed value, as has been described by other groups 1,15 , but to increase, from 2.27 mm at 45 mm CRL to 3.78 mm at 84 mm 11 . In our series, twins with an NT > 99 th percentile and normal karyotype had a 60% prevalence of fetal anomalies and a 20% risk of fetal demise, irrespective of chorionicity.…”

“…It is well known that when an increased nuchal translucency thickness (NT) is observed in the first trimester in chromosomally normal fetuses there is an increased risk for structural abnormalities, mainly cardiac, genetic syndromes and fetal loss 1 . However, the prevalence and significance of increased NT in twin pregnancies has scarcely been investigated.…”

Abnormal Shh and FOXC2 expression correlates with aberrant lymphatic development in human fetuses with increased nuchal translucency

“…Increased NT is also associated with other chromosomal abnormalities like trisomy 18 and 13, structural anomalies such as cardiac defects and several genetic syndromes (Hyett et al, 1997;Souka et al, 2005). Recent studies implicate disturbed lymphatic development as a likely explanation for the origin of increased NT (Haak et al, 2002;Bekker et al, 2005bBekker et al, , 2006a.…”

Aneuploidy and Anomaly Screening

“…Furthermore, high NT is associated with cardiac defects and a wide range of other fetal malformations and genetic syndromes (Hyett et al, 1996a;Souka et al, 1998Souka et al, , 2005.…”