Although the cause of this abnormality in fetal aneuploidy is uncertain, a reversed a-wave is seen in 3% to 4% of euploid fetuses compared to about 70% of trisomy 21 and trisomy 18, 65% of trisomy 13, and 75% of Turner syndrome fetuses [34]. The addition of ductus venosus Doppler assessment to nuchal translucency measurement improves the detection rate of trisomy 21 to 96% with 3% false positive rate [34]. Ductus venosus a-wave abnormalities are also associated with congenital heart disease [35]. In chromosomally normal fetuses with an increased nuchal translucency, a reversed a-wave in the ductus venosus is associated with a 3-fold increase in the likelihood of a major heart anomaly; a normal ductus Nuchal Translucency Evaluation Nuchal Translucency Evaluation The risk of an adverse pregnancy outcome is proportional to the degree of nuchal translucency enlargement; there is an increased risk of intrauterine demise in fetuses with large nuchal translucencies, even in the absence of associated chromosomal or structural abnormalities [22,23]. Although there are no studies that specifically address the optimal management of these pregnancies after the initial US evaluation and diagnostic testing, serial fetal surveillance is usually added to routine prenatal care with periodic US examinations to monitor fetal growth and well-being [2,45]. US Pregnant Uterus Transvaginal A transvaginal US may be advantageous in patients with an increased nuchal translucency, particularly if planning to assess for additional first trimester markers of fetal aneuploidy or screen for major anomalies in women with increased body mass indexes, abdominal wall scarring, or fetal positioning in the lower uterus. Fetal nuchal translucency measurements are similar as long as the same principles for image acquisition are applied, so obtaining a transvaginal measurement is not required if transabdominal imaging is satisfactory [29].
Nuchal Translucency Evaluation at 11 to 14 Weeks Gestational Age. Although the cause of this abnormality in fetal aneuploidy is uncertain, a reversed a-wave is seen in 3% to 4% of euploid fetuses compared to about 70% of trisomy 21 and trisomy 18, 65% of trisomy 13, and 75% of Turner syndrome fetuses [34]. The addition of ductus venosus Doppler assessment to nuchal translucency measurement improves the detection rate of trisomy 21 to 96% with 3% false positive rate [34]. Ductus venosus a-wave abnormalities are also associated with congenital heart disease [35]. In chromosomally normal fetuses with an increased nuchal translucency, a reversed a-wave in the ductus venosus is associated with a 3-fold increase in the likelihood of a major heart anomaly; a normal ductus Nuchal Translucency Evaluation Nuchal Translucency Evaluation The risk of an adverse pregnancy outcome is proportional to the degree of nuchal translucency enlargement; there is an increased risk of intrauterine demise in fetuses with large nuchal translucencies, even in the absence of associated chromosomal or structural abnormalities [22,23]. Although there are no studies that specifically address the optimal management of these pregnancies after the initial US evaluation and diagnostic testing, serial fetal surveillance is usually added to routine prenatal care with periodic US examinations to monitor fetal growth and well-being [2,45]. US Pregnant Uterus Transvaginal A transvaginal US may be advantageous in patients with an increased nuchal translucency, particularly if planning to assess for additional first trimester markers of fetal aneuploidy or screen for major anomalies in women with increased body mass indexes, abdominal wall scarring, or fetal positioning in the lower uterus. Fetal nuchal translucency measurements are similar as long as the same principles for image acquisition are applied, so obtaining a transvaginal measurement is not required if transabdominal imaging is satisfactory [29].