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Nuchal Translucency
Aka: Nuchal Translucency
- See Also
- Antenatal Screening
- Trisomy Findings on Fetal Ultrasound
- Definitions
- Nuchal Translucency
- Posterior fetal neck lucency by Ultrasound
- Indications
- Early Antenatal Screening for Down Syndrome and birth defects
- Protocol
- Timing: 11-13 weeks gestation
- Technique
- Ultrasound used to measure the lucency of the posterior fetal neck
- Measurement requires additional special training and certification
- Precautions
- Do not use Nuchal Translucency alone (combine with serum Aneuploidy Screening)
- Exception: Multiple Gestation pregnancies (serum testing is inaccurate)
- Abnormal Nuchal Translucency is associated with both Aneuploidy and structural defects
- Obtain detailed Fetal SurveyUltrasound at 18 to 22 weeks if abnormal Nuchal Translucency
- Obtain fetal Echocardiogram if abnormal Nuchal Translucency (per ACOG guidelines)
- Efficacy: Down Syndrome detection
- Test Sensitivity: 70%
- Test Specificity: >95%
- Differential Diagnosis: Increased Nuchal Translucency
- Down Syndrome and other Genetic Syndromes
- Major Congenital Heart Defect
- Great Vessel defect
- Fetal malformations, dysplasias, deformations and disruptions
- False Positives (Nuchal Translucency increases 15-20% per week in normal pregnancies)
- References
- Anderson (2009) Am Fam Physician 79(2): 117-24 [PubMed]
- Makrydimas (2005) Am J Obstet Gynecol 192(1): 89-95 [PubMed]
- Salvedt (2005) Ultrasound Obstet Gynecol 25(6): 537-45 [PubMed]
- Souka (2005) Am J Obstet Gynecol 192(4):1005-21 [PubMed]