Objective:To evaluate the value of elevated nuchal translucency(NT) as a screening test for chromosomal abnormalities(especially trisomy 21) in a first trimester ultrasound examination. Methods:A search in Cochrane Library, PubMed, OVID, Springer, China National Knowledge Infrastructure(CNKI) and Chinese Bio-medicine Database(CBM) was performed to identify relevant English and Chinese articles between Jan 1990 and August 2008. Criteria for inclusion were established based on validity criteria for diagnostic research. The eligible studies were collected and analyzed using Meta-DiSc 1.4. Results:Fourteen articles were included, with a total of 162992 fetuses. Eleven articles meeting inclusion criteria were analyzed for the value of screening for chromosomal abnormalities by nuchal translucency thickness above the 95th percentile for gestational age. The pooled sensitivity and specificity was 78.8%-92.1% respectively, AUC=0.891. Twelve articles meeting inclusion criteria were analyzed for the value of screening for trisomy 21 by nuchal translucency thickness above the 95th percentile for gestational age. The pooled sensitivity and specificity was 81.3%-92.6% respectively, AUC=0.883. Conclusion:The results suggest that screening for chromosomal abnormalities(especially trisomy 21) by nuchal translucency thickness above the 95th percentile for gestational age has a high sensitivity, specificity, accuracy and is suitable for prenatal screen.