Gynecology & Obstetrics
Open Access

Abstract

Evaluation of Trisomy 21 Screening by Fetal Nuchal Translucency Thickness, Maternal Age and Biochemical Serum in the South of Vietnam

Xuan-Hong Tomai, Jean Pierre Schaaps and Jean Michel Foidart

Aims: This study aimed to evaluate the most effective approach screening of trisomy 21 in the first trimester in Vietnam

Method: A prospective study carried out during 1 year. All pregnancies screened the risk of trisomy 21 by association of the fetal nuchal translucency, maternal age and biochemical serum (free β-hCG and PAPP-A) as a combined test in the first trimester. The amniocentesis was used to diagnose trisomy 21. In each 4 approaches screening (the isolated maternal age, the maternal age and fetal NT thickness, maternal age and biochemistry, and combined test), the detection rate and false positive rate of trisomy 21 were calculated to find out the most effective screening method.

Results: Followed up 2500 singleton pregnancies, the incidence of trisomy 21 was 0.6% (16/2500) (95%CI 0.4- 1.0%). The absence of nasal bone and poly-malformation were the essential ultrasonographic findings of Down’s syndrome. An increased fetal NT (≥ 2.4 mm) related significantly to this aneuploidy (OR=58.6, 95%CI 17.3-251, p < 0.0001). In comparison of 4 approaches screening, the most possibility of Down’s syndrome detection was the combined test (87.5% of sensitivity for 2.6% of false positive rate).

Conclusion: The combined test was effectively screening method for Down syndrome in Vietnamese pregnancies.