Abstract： Objective To evaluate the efficiency of combined screening for chromosomal abnormalities in the first trimester and the ultrasound characteristics of these fetuses.Methods Retrospective study for 5000 singleton pregnancies by combined screening of trisomies 21,18,13 and Turner syndrome.Risk algorithms were developed for calculation of patient-specific risks for each of the three trisomies based on maternal age,fetal nuchal translucency,free β human chorionic gonadotropin and serum pregnancy associated plasma protein A at 11 to 13 +6 weeks of pregnant.The value of nuchal translucency (NT) and β-hCG and pregnancy-associated plasma protein A (PAPP-A) level were inputted computer,and calculate the risk value (≥ 1 ∶ 270) by automatic analysis software.Two hundred and four cases with high risk were performed transabdominal chorionic villus biopsy to detect the fetal chromosomal karyotypes.Meanwhile,other ultrasonic characteristics of fetal were elevated.Results (1) Five thousand cases of pregnant women were detected,including 4983 normal cases,62 cases were induced labor for a variety of reasons in the second trimester,including 40 cases with normal karyotype but with congenital heart disease,17 cases of chromosome abnormalities (9 cases trisomy 21,2 cases trisomy 18,1 cases trisomy 13,4 cases 45X),2 cases spina bifida,2 cases digestive tract obstruction,1 cases giant bladder.One case with low risk of fetal chromosomal abnormalities in combined screening,but high risk of age (maternal age were over 40 years old),it was 21 trisomy syndrome after the prenatal diagnosis.(2) Five cases of nasal bone loss in 9 cases of trisomy 21 (5/9),5 cases with three tricuspid regurgitation (5/9),4 cases of venous ductus a wave flow reverse (4/9),3 cases of fetal nasal bone loss accompanied by tricuspid regurgitation and venous ductus a wave flow reverse (3/9).One case of nasal bone loss in 2 cases of trisomy 18,2 cases were tricuspid regurgitation and venous ductus a wave flow reverse.Two cases in 4 cases of 45X had venous ductus a wave flow reverse.There were 8 cases (0.16％) nasal bone absence in 4983 cases of normal karyotype fetus,48 cases (0.96％) of tricuspid regurgitation and 44 cases (0.88％) of venous ductus a wave flow reverse.Thirty-two cases in 40 cases (80％) of fetal congenital heart disease were tricuspid regurgitation,30 cases of venous ductus a wave flow reverse (75％).Eight cases of nasal bone absence normal karyotype fetus were found the nasal bone at 20 weeks gestation.Conclusion Combination screening of nuchal translucency with serum markers in the first trimester were high detection rate and low false positive rate; a wave reversion and fetal nasal bone absence accompanied by tricuspid regurgitation can improve the detection rate of abnormal karyotype; abnormalities ultrasound marker may be associated with fetal congenital heart disease at 11-13 +6 weeks of pregnancy.