目的:探讨孕中期母血清筛查21-三体和18-三体综合征及神经管缺陷胎儿阳性病例中的染色体异常情况。对高风险人群进行后续诊断,及早发现患病胎儿,防止其出生。方法:采用时间分辨免疫荧光法,对风险值计算21-三体和18-三体切割值,对阳性病例进行染色体核型分析。结果:在7 717例产前筛查中共筛查出高风险孕妇295例,其中21-三体综合征191例,阳性率为2.48%;18-三体综合征32例,阳性率为0.41%;神经管缺陷高风险72例,阳性率0.93%。对阳性病例中的63例进行羊水胎儿染色体核型分析,确诊21-三体综合征、18-三体综合征各2例;神经管缺陷病例经B超确诊脊柱裂、唇腭裂、内脏外翻各1例,先天性心脏病(先心)2例。结论:孕中期血清甲胎蛋白(AFP)、游离-β-绒毛膜促性腺激素(β-HCG)检测,可筛查出胎儿罹患21-三体综合征、18-三体综合征和神经管缺陷的高危个体,通过产前诊断,可早确诊、早干预。 Objective: To investigate the chromosomal abnormalities in second trimester and 18-trisomy syndrome and neural tube defect-positive fetuses in second trimester maternal serum screening. Follow-up diagnosis of high-risk groups, early detection of the fetus to prevent their birth. Methods: Time-resolved immunofluorescence method was used to calculate the 21-trisomy and 18-trisomy values ​​of risk, and the karyotypes of positive cases were analyzed. RESULTS: A total of 295 high-risk pregnant women were screened out of 7,717 antenatal screening patients, including 191 cases of 21-trisomy syndrome with a positive rate of 2.48%. Twenty-eight cases of trisomy 18 had a positive rate of 0.41% 72 cases had high risk of neural tube defects, the positive rate was 0.93%. The positive cases of 63 cases of amniotic fluid fetal karyotype analysis, diagnosis of 21-trisomy, 18-trisomy syndrome in 2 cases; neural tube defects by B-diagnosis of spina bifida, cleft lip and palate, visceral valgus 1 in each case, congenital heart disease (heart) in 2 cases. Conclusion: The detection of serum alpha-fetoprotein (AFP) and free beta-chorionic gonadotropin (beta-HCG) during the second trimester of pregnancy can screen out the fetuses with trisomy 21, trisomy 18 and neural tube Defective high-risk individuals, prenatal diagnosis, early diagnosis, early intervention.