T. H. Oanh Quach, K. Y. Trang Bui, T. N. Hoang Nguyen, N. A. Phu Tran, T. L. Anh Nguyen
Background and objective: Currently, screening and prenatal diagnosis of chromosomal disorders has become popular in big hospitals in Vietnam. One of the most popular rapid tests in aneuploidy diagnostic is quantitative fluorescence PCR. Prenatal diagnosis is indicated for high-risk pregnancy screened by screening tests (combined test, triple test) or ultrasound (fetal anatomic defects, such as congenital heart defect or markers suggestive of fetal aneuploidy like a nuchal translucency, thickened nuchal fold, absent nasal bone, renal pyelectasis, or echogenic bowel…). However, research about the ratio of aneuploidy in these each screening test has not been carried in Vietnam. This study is evaluating the correlations between the screening test, ultrasonography results and results of chromosomal analysis on fetal cells.
Methods: Analyzing 5,557 QF-PCR results of amniotic fluid samples from pregnant women with high risk from Jan to Dec 2014.
Results: In our study, we identified 242 cases (4.35%) with aneuploidy (of which 132 cases of trisomy 21, 78 cases of trisomy 18, 11 cases of trisomy 13, 21 cases of other chromosomal abnormalities). The most cases of amniocentesis are pregnancy with high risk of biochemical test: 3,955/5,557 cases (71%). The ratio of high risk pregnancies screened by combined test is higher than this by triple test: 4.7% (107/2,275) compared to 2.44% (41/1,680). The ratio of trisomy 21 is highest in cases of absent nasal bone: 20.8% (40/192). Multiple congenital cases are the highest ratio of trisomy 18: 61% (11/18 cases).
Conclusions: This report confirms the importance of prenatal screening and diagnosis in detecting aneuploidy. It also helps obstetricians and geneticists in counseling and indicating invasive techniques for high risk pregnancies.
