Down's syndrome screening and antenatal diagnosis in the pregnant metaphase

? Objective:To explore the practical value of Down's screening and antenatal diagnosis in preventing and decreasing chromosomal disease and congenital birth defect. Methods: Serum AFP and free-β-HCG level of pregnant women (15~20 weeks) were detected by time-distinguished fluorescence immunoassay. Down's syndrome risk value was calculated with Multicalc software, its cut-off value was 1:274. The pregnant women whose value are higher than or equal to 1:274 would be at high risk and need to exclude fetal abnormal karyotype combing diagnoses with ultrasonic B examination, amniocentesis or fetal blood. Results:3 685 pregnant women accepted antenatal screening, 220 cases of them were detected at high risk with Down's syndrome, and positive rate was 1.22%. Of 118 cases diagnosed by amniocentesis or fetal blood, 11 cases with fetal abnormal chromosome, the detectable rate was 9.32%; 45 cases at high risk of Down's syndrome, the positive rate was 1.22%. In the high-risk pregnant women, 10 cases with abnormal fetal were found by ultrasonic B. Conclusion:Serum AFP and free-β-HCG level of pregnant women were effective indexes to screen abnormal fetal combining with antenatal screening of amniotic, fetal blood or ultrasonic B, which would be a practical method of preventing congenital defect. 〔