Cribado cromosómico del primer trimestre. Resultados en gestaciones tras reproducción asistida

Objective

To determine the effectiveness of the combined test for aneuploidies in the first trimester of spontaneous pregnancies in comparison with pregnancies following assisted reproductive technology (ART).

Materials and methods

We performed a retrospective study of 1675 triple tests performed in the first trimester in our center, including pregnancy-associated plasma-A (PAPP-A) and the free fraction of the β subunit of human chorionic gonadotropin (free β-hCG), maternal age and nuchal scan. Of these, 1299 (77.5%) were spontaneous pregnancies and 376 (22.5%) were pregnancies following ART. The cut-off point for recommending an invasive test was 1/270.

Results

The combined test was carried out in 74 twin pregnancies, with two false-positive results. Among single pregnancies, 70 positive triple tests were obtained, 3.79% of spontaneous pregnancies and 6.84% of ART pregnancies. Eleven chromosomal abnormalities were found, nine in spontaneous pregnancies and two in ART pregnancies. The sensitivity of the test was 89% in spontaneous pregnancies and 100% in ART pregnancies. The specificity was 96% and 93.77%, respectively.

Conclusions

The first trimester triple test has high sensitivity and specificity in single pregnancies, whether spontaneous or following ART. The rate of positive triple tests is higher in pregnancies following ART.