Resumo

ILLESCAS M, Tamara et al. Estudio descriptivo del cribado de cromosomopatías en el primer trimestre de la gestación, en el Hospital Clínico San Carlos de Madrid, España. Rev. chil. obstet. ginecol. [online]. 2011, vol.76, n.5, pp. 318-324. ISSN 0717-7526.  doi: 10.4067/S0717-75262011000500006.

Background: Screening for aneuploidies, mainly trisomy 21, during the first trimester of gestation, was introduced in the '90s and is based on a calculation of the risk through the combination of maternal age, nuchal translucency (NT) and biochemical parameters (PAPP-A and fBHCG). By means of this combination we can obtain a detection rate for aneuploidies of 85-90%, with a false positive rate of 5%. Objective: To describe our population and analyze our results related to combined screening for aneuploidies, during the period of time it has been performed in our hospital. Methods: Observational study of all pregnant women who attended Hospital Clínico San Carlos for screening of chromosomopaties during first trimester of gestation, from July 1999 to December 2009. Results: Sample size was 21,194 single pregnancies, with 12,5% of women with more than one gestation, and 141 cases of aneuploidy (6,6%). We describe the characteristics of our population and the distribution of the parameters studied. Combined screening had a detection rate of 70% with a false positive rate of 2,3%. Conclusion: Screening for aneuploidies during first trimester of gestation, in Hospital Clínico San Carlos, has a lower detection rate than previously reported. However, the false positive rate is very low.

Palavras-chave : Screening; aneuploidies; first trimester; pregnancy.