Evaluation of the cytogenetical results of 4707 cases diagnosed with amniocentesis

Abstract

PURPOSE: Amniocentesis is a very crucial diagnostic procedure for preventing the birth of genetically defective fetuses in order to decrease the prevalence of genetic diseases in populations.

METHODS: The karyotyping of 4707 fetuses was carried out in our department during the years of 2000-2009 from the samples of amniotic fluids, CVS, fetal tissues and urines which were sent from departments of Gynecology and Obstetrics of Balcali Hospital and other regional hospitals.

RESULTS: The mean maternel and gestational age of pregnant women evaluated for prenatal diagnosis were 29.1 years of age and 18.8 months respectively. Among 4707 fetuses that were karyotyped; 2284 fetuses were males and 2205 fetuses were females and 218 (4.63%) fetuses had various chromosomal abnormalities. Consequently, male to female ratio of fetuses that were examined was 1.03. The advanced maternal age pregnancies followed by positive triplescreening were related to the highest rate of chromosomal abnormalities. The mean age of pregnant women having fetuses with chromosomal abnormalities was found to be 33 years of age which suggest that fetal chromosomal abnormalities were associated with maternal age. Numerical chromosomal abnormalities predominated the structural chromosomal abnormalities (55.5% vs to 44.5%). The numerical chromosomal abnormalities with an incidence of 47.9% trisomy 21, 14.1% trisomy 18, 8.7% Klinefelter Syndrome, 7% monosomy X, 6.6% trisomy 13, 1.7% trisomy X, 1.7% XYY Syndrom, 10% mosaics and the others represented the remaining. Of the structural abnormalities 35% were balanced while the 4% were unbalanced. The frequent structural abnormalities were 25.3% 46, XX/XY, inv(9)(p11; q12) and 19.5% 46, XX/XY, inv(9)(p11; q13). Balanced and unbalanced translocations, deletions and duplications were alsocontributed to chromosomal abnormalities in lesser extent.

CONCLUSIONS: Corollary to literature and our findings revealed that the advanced maternal age and certain environmental factors can increase the risk of fetal chromosomal abnormalities. Fetal chromosomal abnormalities representing 4.63% in our study group is crucial and underlines the importance of prenatal diagnosis for healthier pregnancies.