Abstract： Objective To study the clinical outcome of fetus with thickened nuchal translucency,and to explore the clinical value of ultrasonography in testing nuchal translucency (NT) thickness for evaluating fetal prognosis. Methods NT test was routinely performed in 4081 fetuses between 11- 13+6 weeks of gestation and with head-buttock length between 45-84 mm. Fetuses would be taken with thickened NT if NT thickness≥2.5 mm. The clinical outcome of fetuses with NT thickness was followed up. The NT thickness was classified into four groups (Group A: 2.5-3.4 mm, Group B: 3.5-4.4 mm, Group C: 4.5-5.4 mm and Group D: 5.5-6.4 mm). Ridit analysis was used for comparing the clinical outcomes of fetuses with various NT thickness, and rank correlation analysis was applied for analyzing correlation of NT thickness with fetuses survival rate. Results Thickened NT was observed in 58 fetuses by ultrasound, of whom, NT≥6.5 mm appeared in 6, and these 6 cases were aborted during early pregnancy. The other 52 cases had NT ＜6.5 mm, 4 of whom had chromosomal abnormalities, 10 cases were with normal chromosomes but accompanied by malformation or genetic syndrome, 1 case ceased development in the first trimester, no abnormity to birth was observed in other 33 cases and 4 cases lost follow up. The clinical outcomes in fetus with various NT thickness had significant differences (P＜0.05). Survival rate of fetuses decreased as NT thickened [Group A: 81.8% (27/33), Group B: 62.5%(5/8), Group C: 25% (1/4), Group D: 0% (0/3),r=-0.993, P＜0.05 ]. Conclusion Ultrasonography for testing NT thickness is an important reference value for making early evaluation on prognosis of fetuses in clinical.