摘要：Objective: This study was undertaken to evaluate the performance of a 1- stop clinic for first- trimester assessment of risk (OSCAR)for trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) thickness, and maternal serum- free β - human chorionic gonadotrophin (hCG) and pregnancy- associated plasma protein- A (PAPP- A). Study design: OSCAR was carried out in 30,564 pregnancies at 11 to 13+ 6 weeks. Patient- specific risks for trisomy 21 and detection and falsepositive rates were calculated. Results: The median maternal age was 34 (range 15- 49) years. Chromosomal abnormalities were identified in 330 pregnancies, including 196 cases of trisomy 21. The estimated risk for trisomy 21 was 1 in 300 or greater in 7.5% of the normal pregnancies, in 93.4% of those with trisomy 21 and in 88.8% of those with other chromosomal defects. Conclusion: The most effective method of screening for chromosomal defects is by first- trimester fetal NT and maternal serum biochemistry.

摘要：Objective: The purpose of this study was to examine the sonographic features of trisomy 13 at 11 to 13+ 6 weeks of gestation. Study design: This was a retrospective study that examined the features of trisomy 13 at the ultrasound scan at 11 to 13+ 6 weeks of gestation, which in our center is performed for the measurement of crown-rump length, nuchal translucency thickness, and fetal heart rate and the examination for major defects. Results: In the 181 fetuses with trisomy 13, there were holoprosencephaly, exomphalos, and/or megacystis in 92 fetuses (50.2% ), fetal heart rate above the 95th percentile in 129 fetuses (71.3% )- , and nuchal translucency above the 95th percentile in 141 fetuses (77.9% ). There was no significant association between nuchal translucency and fetal heart rate, and it was estimated that inclusion of fetal heart rate in nuchal translucency screening can improve the detection rate of trisomy 13 by approximately 5% . Conclusion: At the 11 to 13+ 6- week scan, the measurement of fetal nuchal translucency and fetal heart rate and fetal examination for holoprosencephaly, exomphalos, and megacystis can identify >90% of fetuses with trisomy 13.