Prenatal diagnosis using the triple test.

METHODS

A screening study performed on 2,803 pregnant women using the "triple test" is reported.

RESULTS

Nine hundred and twenty-one had a high prior risk, having > 35 years while, after the screening, only 201 women had a positive test at risk higher than 1:270, and underwent to amniocentesis. The detection rate (DR) for all abnormalities was 91% while for Down's syndrome (DS) it was 87.5% and for neural tube defects 85.5%. Foetal abnormalities were detected in 20 cases (1:10) while 181 were false positive cases (6.5%), of which 151 for DS (5.4%). False negative were observed only in 2 cases within 2,339 at term pregnancies.

CONCLUSIONS

The authors retain that high DR is related to the exactness of determination of gestation age calculated by scan and to the homogeneity of the examined population.