[Prenatal serum screening of aneuploidy and of neural tube defects in the second trimester of pregnancy among the population of Luxembourg. Evaluation of risk by the triple test (AFP+THCG+UE3)].

AIM

The value of the antenatal maternal serum screening by triple test during second trimester pregnancy has been examined for the Luxembourg population.

SUBJECT

In collaboration with the gynaecologists using our triple test, the performance of the screening has been evaluated against the outcome (before and at birth) of all the pregnancies screened between end of 1991 and 28.02.1996. In particular, the effectiveness of Down's syndrome (Trisomy-21) detection has been ascertained.

RESULTS

A total of 6760 pregnancies has been screened. Women's age ranged from 16 to 44 years, with a mean age of 28.4 years, 5.68% had > or = 35 years. The screening has been positive (at higher risk) for 7.25% pregnancies, wherein 5.98% were at higher risk for Trisomy-21 and 1.27% at higher risk for Neural Tube Defects (NTD). Among the screen positives, 20.79% were aged > or = 35 years and 79.21% were < 35 ans. There have been 12 Down's cases present among the 6760 pregnancies, 9 of them had in the screening a calculated risk higher than the cut-off (1:250). The detection rate (sensitivity) for Trisomy-21 was 75%, the specificity was 94.15% and the predictive value of a positive test was 2.23%.

CONCLUSION

This study shows that our antenatal maternal serum screening compares favorably with the other screenings realized by reference centres and the results produced are reliable.