26 803例中期妊娠妇女血清筛查胎儿染色体异常的结果分析

目的 评价江苏省以人群为基础的中期妊娠母血清筛查胎儿染色体异常的效率。方法 采用分层抽样和整群抽样相结合的多阶段抽样方法,在江苏省苏南、苏中、苏北地区以乡（镇）或街道为单位,抽取95个项目点,抽样时间为1年。项目点所有妊娠15-20周的妇女接受母血清甲胎蛋白（AFP）、人绒毛膜促性腺激素游离β亚单位（f-βHCG）检测,同时B超确定孕龄,在孕妇体重校正的基础上,计算胎儿染色体异常的风险值。对高风险者,在知情同意的基础上进行确诊检查。随访所有活产儿至出生后的0．5～4岁。结果 95个项目点1年中共有妊娠妇女27313名,参与产前筛查者26803例,占同期总妊娠妇女的98％。孕妇平均年龄25．1岁,≥35岁者占1．7％。母血清筛查为唐氏综合征高风险者1244例、爱德华综合征高风险者105例,筛查阳性率分别占筛查人群的5％、0．4％。最终妊娠结局显示染色体异常胎儿及婴幼儿共20例,其中唐氏综合征9例、爱德华综合征5例,其他染色体异常6例。本组中期妊娠母血清AFP、f-βHCG联合筛查唐氏综合征的检出率为56％（5／9）,爱德华综合征检出率80％（4／5）。结论 在严格质量控制的基础上,妊娠中期母血清AFP、f-βHCG二联筛查胎儿染色体异常有较高的检出率,但良好的筛查成本效益比与目标出生缺陷的人群发病率有关。

Serum screening of fetal chromosome abnormality during second pregnancy trimester: results of 26,803 pregnant women in Jiangsu Province

OBJECTIVE: To evaluate the efficiency of the second trimester screening for fetal chromosomal anomaly using maternal serum marker. METHOD: 27,313 pregnant women with the gestational age of 15 - 20 weeks were selected by stratified combined with cluster sampling from 13 counties over Jiangsu province and 5 townships, towns, or subdistricts from 6 randomly selected cities from southern, central, and northern Jiangsu, totally 95 communities, between July 2002 and November 2006. Questionnaire survey was conducted. Body weight was taken. Ultrasonography was used to confirm the gestational age. Peripheral blood samples were collected to detect the maternal serum alpha-fetoprotein (AFP) and free beta human chorionic gonadotrophin (f-betaHCG). The risk values of Down syndrome and Edwards syndrome were calculated. The women at high risk of Down syndrome and Edwards syndrome for their fetuses were recommended to receive genetic counseling and amniocentesis. All babies were followed up until six months to four years of age after birth. RESULTS: 26,803 of the 27,313 women (98%) were screened. The average was 25.1, and 1.7% of them were over 35. Serum screening showed that 1,244 (5%) were Down syndrome positive and 105 (0.4%) were Edwards syndrome positive. The final pregnant outcomes showed that 20 cases presented chromosomal abnormalities, of which 9 cases suffered from Down syndrome, 5 cases Edwards syndrome, and 6 cases other chromosomal abnormalities. The detection rate of Down syndrome and Edwards syndrome were 56% and 80% respectively. CONCLUSION: Under good quality control high prenatal detection rate of fetal chromosomal abnormalities can be reached by screening of maternal serum AFP and f-betaHCG during the second pregnancy trimester. Good cost-effectiveness depends on the incidence of targeted birth defects.