Current status of prenatal diagnosis in Cuba: causes of low prevalence of Down syndrome.

Abstract

To analyze trends in cytogenetic prenatal diagnosis in Cuba and to analyze possible causes leading to a low Down syndrome prevalence in a country where the triple test is not available. An analysis of the Cuban program in prenatal cytogenetic diagnosis from 1984 to 2012 was conducted. Results are described, with particular emphasis on indications, abnormal results, types of invasive procedures, and terminations of pregnancy. Cytogenetic prenatal diagnostic analyses (n = 75,095) were conducted; maternal age was the indication for 77.9% of the amniocenteses and chorionic villus samplings. The detection rate of chromosomally abnormal pregnancies was 2.3% for maternal age and increased to 8-9% for other indications. When a chromosomal abnormality was identified, 88.5% terminated the pregnancy. In 2002, the live birth prevalence of Down syndrome was 8.4 per 10,000 live births, and in 2012, 7 per 10,000. Prenatal diagnosis in Cuba has contributed to a significant reduction in chromosomal aberrations. The impact increased because of the demographic trends of the population, the high index of terminations of pregnancy, and the establishment of a network of cytogenetic laboratories throughout Cuba.