目的 探讨孕中期母血清筛查21-三体、18-三体高风险病例的染色体异常情况。方法 对沈阳地区153 910例怀孕15～20+6周的妇女采用时间分辨荧光法进行母血清常规二联筛查，风险值计算21-三体以1/270，18-三体以1/350为切割值，筛查出的高风险孕妇进行羊膜腔穿刺，细胞培养及染色体分析。结果 153 910例筛查中有8559例为高风险病例，占筛查总人数的5.56%。其中3546例进行染色体分析（占高风险总数的41.4%），发现76例异常核型，其中21-三体21例，18-三体15例，性染色体异常11例，其他核型异常29例，异常发生率2.14%。结论 产前筛查和诊断能减少染色体异常患儿的发生，提高出生人口素质。
Objective To study the chromosome analysis after a Down’s syndrome or Edward’s syndrome screen-positive result by maternal serum during the second trimester. Method 153 910 women at 15～20+6 weeks gestation were screened by maternal serum AFP and Free β-hcG using the time resolval fluorimmunassay(TRFIA).Then the screened high-risk women were diagnosed by amniocentesis, cell culture and chromosome analyses. By use of a 1:270 midtrimester Down’s syndrome risk, a 1:350 midtrimester Edward’s syndrome risk cut off value. Results 8559 patients were screen high-risk for trisomy 18 or trisomy 21, corrected screen-positive rate 5.56% .Karyotype were reviewed for 3456 of these patients who received prenatal chromosome analysis. In addition to 21 cases of Down’s syndrome, 15 cases Edwards syndrome and 11 cases abnormal sex chromosome were found among the 3546 pregnant women (2.14%).Conclusions The prenatal screening and diagnosis can reduce the birth of abnormal chromosome patients and improve the population quality.
