A karyotype analysis on 561 cases of fetuses and discussion on the indications for prenatal diagnosis

Objectives To analyze the chromosomal karyotypes of fetus,and discuss the detection rates of chromosomal abnormalities under different indications for prenatal diagnosis.Methods Cytogenetic prenatal diagnosis were performed on a cohort of pregnant women with different indications in the second-or third-trimester.Detection rates of fetal chromosomal abnormalities under each indication were compared.Results The success rate of amniotic fluid cell culture was 95.1%(562/591),and 33 cases of abnormal karyotypes were found.The detection rate of abnormality was 5.9%(33/562),including 15 cases of triploid syndromes(45.4%),8 cases of Down's syndrome,4 cases of 18-trisomy,and 1 case of 16-trisomy syndrome.The detection rate of abnormal karyotypes was 50% in the pregnant women who or which couple was a carrier of constitutional chromosome abnormality,10% of the fetuses with abnormal ultrasound founding,5.6% of pregnant women elder than 35 years old,and 2.6% in high risk pregnancy by serum prenatal screening.Conclusion A carrier of chromosomal abnormality of one of the couple,fetal abnormalities found by ultrasound,elder maternal age,and a high risk result by serum prenatal screening are the most important genetic indications for prenatal diagnosis.