Analysis of chromosomal karyotypes on 1790 advanced pregnancy women during the second and third trimesters of gestation

Objective: To analyze the fetal chromosomal karyotypes and trisomy incidence with age from amniotic fluid and cord blood samples obtained by cordocenteses during the second and third trimesters,and to investigate the types of chromosomal abnormalities,as well as the relationship between the abnormal karyotypes and the indications of prenatal diagnosis.Methods: Through 2010 to 2011 in our hospital to genetic clinics in 1790 cases of elderly pregnant women(≥35)undergoing amniocentesis or umbilical cordblood draw,through cell culture training and karyotype analysis.Analysis of the abnormal chromosome karyotype in women of advanced maternal age.Results: 158 cases of chromosome abnormalities were detected among 1790 prenatal diagnostic samples with the abnormal rate of 8.8%.The incidences of trisomy 21 is different among the pregnant women with different ages.The ration is 1.06% in 35-37 years old,1.42% in the 38-40 years old,2.08% is over 41 years old.Conclusions: Risk of fetal chromosome abnormalities is higher in advanced pregnant women,appropriate techniques should be used to screen fetal chromosomes during different gestation weeks in advanced pregnant women.