Prenatal cytogenetic diagnosis in Spain: analysis and evaluation of the results obtained from amniotic fluid samples during the last decade

• Published in: European journal of obstetrics & gynecology and reproductive biology 2011-08, Vol.157 (2), p.156-160
• Main Authors: Mademont-Soler, Irene, Morales, Carme, Clusellas, Núria, Soler, Anna, Sánchez, Aurora
• Format: Article
• Language: English
• Subjects: Amniocentesis - methods; Biological and medical sciences; Chromosome Aberrations - statistics & numerical data; Chromosome Disorders - diagnosis; Chromosome Disorders - epidemiology; Cytogenetics - methods; Down Syndrome - diagnosis; Down Syndrome - epidemiology; Female; General aspects. Genetic counseling; Genetic Counseling; Genetic counselling; Gynecology. Andrology. Obstetrics; Humans; Karyotype; Karyotyping - methods; Maternal Age; Medical genetics; Medical sciences; Nuchal translucency; Nuchal Translucency Measurement; Obstetrics and Gynecology; Pregnancy; Prenatal diagnosis; Prenatal Diagnosis - methods; Prevalence; Retrospective Studies; Spain; Ultrasonography, Prenatal; Ultrasound abnormalities
• ISSN: 0301-2115; 1872-7654
• DOI: 10.1016/j.ejogrb.2011.03.016

Abstract Chromosome abnormalities are one of the main causes of congenital defects, and establishing their frequency according to the different clinical indications for invasive procedure during pregnancy is especially important for genetic counselling. We analyzed the results of 29,883 amniotic fluid samples referred to our laboratory for cytogenetic studies from 1998 to 2009, which constitutes the largest series of cytogenetic analysis performed on amniotic fluid samples in Spain. The number of samples received tended to increase from 1998 to 2005, but after 2005 it decreased substantially. Cytogenetic results were obtained in 99.5% of the samples, and the detected incidence of chromosome abnormalities was 2.9%. Of these, 48.1% consisted of classical autosomal aneuploidies, trisomy 21 being the most frequent one. The main clinical indications for amniocentesis were positive prenatal screening and advanced maternal age, but referral reasons with highest positive predictive values were, excluding parental chromosome rearrangement, increased nuchal translucency (9.2%) and ultrasound abnormalities (6.6%). In conclusion, performing the karyotype on amniotic fluid samples is a good method for the detection of chromosome abnormalities during pregnancy. The number of cytogenetic studies on amniotic fluid has now decreased, however, due to the implementation of first trimester prenatal screening for the detection of Down syndrome, which allows karyotyping on chorionic villus samples. Our results also show that both ultrasound abnormalities and increased nuchal translucency are excellent clinical indicators for fetal chromosome abnormality.