| Background and purpose:Prenatal diagnosis,also known as intrauterine diagnosis,is a direct and indirect method of detecting the health of the foetus during pregnancy in order to prevent the birth of children with severe genetic disorders,mental retardation and congenital malformations.Karyotyping is currently the most widely used prenatal diagnostic technique,and with the advent of molecular biology and gene sequencing,chromosomal microarray analysis(CMA)has emerged as a powerful complement to karyotyping.By analysing the karyotype and microarray results of amniotic fluid cells from pregnant women with different indications for amniocentesis,the difference in the detection rate of chromosomal abnormalities between karyotype analysis and chromosomal microarray analysis can be compared,thus enabling more accurate guidance for genetic counselling and assessment of pregnancy outcome.Methods:In this study,a retrospective cohort study was conducted to collect a total of 1888 cases of pregnant women with amniocentesis at prenatal diagnostic center of the first hospital of Jilin University from June 2021 to August 2022.1811 cases of pregnant women with amniocentesis who met the statistical criteria were finally included according to the inclusion and exclusion criteria and were grouped according to the different indications for amniocentesis.Using statistical methods,we analyzed the correlation between each prenatal diagnostic indication and chromosomal abnormalities,and compared the detection rate of chromosomal abnormalities found by karyotype analysis and chromosome microarray analysis.Results:The detection rates of chromosomal abnormalities in 1811 fetuses by CMA and karyotype analysis were 18.61% and 10.16%,respectively.CMA detected an additional 10.99% of chromosomal abnormalities compared with conventional karyotype analysis.The difference in detection rate of chromosomal variants between the CMA analysis and the karyotype analysis was large and statistically significant(X~2=52.480,P<0.01).Among the different indications for amniocentesis,the detection rate of chromosomal abnormalities was the highest in both karyotype analysis and CMA in the high-risk group for NIPT testing,with p<0.01 compared with all other groups except the group with chromosomal abnormalities in either spouse,which was significantly different and statistically significant.The comparison of the detection rate of chromosomal variants was statistically significantly different in the advanced age group,the group with abnormal serological screening results,the group with high risk of NIPT,the group with abnormal fetal ultrasonography,and the group with adverse pregnancy history(P<0.01).In the group with advanced age as an indication for amniocentesis: the chromosomal abnormality detection rates by CMA and karyotype analysis was13.76% and 4.76%,respectively,in the group with advanced age as an indication only,and an additional 11.11% of chromosomal abnormalities were detected by CMA compared with conventional karyotype analysis.A statistically significant difference was observed in the detection rates of chromosome abnormalities in both CMA and karyotype analysis when comparing the advanced age group with one other indication for puncture and the group with two or more other indications for puncture(P<0.01);the pregnant women of advanced age were divided into three groups based on age thirty-five to thirty-seven,thirty-seven to forty,and >40.There was a statistically significant difference,suggesting that the rate of detection of abnormal fetal karyotype increased with increasing maternal age.In the group with abnormal serologic screening results as an indication for amniocentesis: in the group with abnormal serologic screening results as an indication for puncture only,the detection rate of abnormal chromosomal results was 7.59% and 2.95% for CMA and karyotype analysis,respectively,which could detect an additional 6.33% of chromosomal abnormalities compared to conventional karyotype analysis.When comparing the detection rate of CMA and karyotype analysis of chromosomal abnormalities in the group with high risk of Down’s screening combined with one other puncture indication and the group with two or more other puncture indications(P<0.05),the difference was statistically significant.When comparing the detection rates of CMA and karyotype analysis in the group with one other puncture indication and the group with two or more other puncture indications in pregnant women at critical risk for Down’s syndrome screening(P>0.05),the differences were not statistically significant.In the group with high risk of NIPT as the indication for amniocentesis: In the group with NIPT as the indication for puncture only,the detection rate of chromosomal abnormalities in CMA was 43.48%,the diagnostic compliance rate of trisomy 21(including chimerism)was 68.97%,the diagnostic compliance rate of trisomy 18 was 7.69%,the diagnostic compliance rate of trisomy 13 high risk group was 43.08%,the diagnostic compliance rate of sex chromosome aneuploidy(including chimerism)was The karyotype analysis showed a detection rate of 30.98%for chromosomal abnormalities,72.41% for trisomy 21(including chimerism),7.69%for trisomy 18,and 43.08% for sex chromosome aneuploidy(including chimerism).The differences were not statistically significant when comparing the detection rate of CMA and karyotype analysis of chromosomal abnormalities in the group with high risk of NIPT detection combined with one other puncture indication and the group with two or more other puncture indications(P>0.05).Among pregnant women with an ultrasound-only abnormality as an indication for puncture,the detection rate for chromosomal abnormalities by CMA and karyotype analysis was 15.18% and 4.36%,respectively,and the detection rate of chromosome abnormalities by CMA was 12.39% greater than that obtained by karyotype analysis;there was a statistically significant difference in the detection rate of fetal chromosomal abnormalities in the soft marker group combined with structural ultrasound abnormalities compared to all other groups(P<0.05).The detection rate of fetal chromosomal abnormalities in the group of soft markers combined with ultrasound structural abnormalities was statistically different from that in other groups(P<0.05),and the detection rate of chromosomal abnormalities in other groups was not statistically different(P>0.05);the difference between the group of pregnant women with NT thickening only and the group of pregnant women with NT thickening combined with fetal ultrasound structural abnormalities was statistically significant with P<0.05.Chromosomal abnormalities were detected at a rate of 10.14% by CMA and 1.45% by karyotype analysis,in the group with adverse pregnancy history as the indication for amniocentesis,and the detection rate of fetal chromosome abnormalities by CMA was 9.35% greater than that obtained by karyotype analysis.Comparing the detection rate of chromosomal abnormalities by CMA and karyotype analysis in the group with bad pregnancy history combined with one other indication and the group with two or more indications(P<0.01),there was a significant difference and statistically significant.In the group with chromosomal abnormalities in either spouse as the indication for amniocentesis: In the group with chromosomal abnormalities in either spouse as the indication for amniocentesis,for example,the detection rates of chromosomal abnormalities by CMA and karyotype analysis were 10.29% and 22.06%,respectively,and the detection rate of chromosomal abnormalities by karyotype analysis was 19.18% higher than the detection rate by CMA analysis.When comparing the detection rates of chromosomal abnormalities in the group with one other indication and the group with two or more indications for CMA and karyotype analysis in pregnant women with chromosomal abnormalities in either spouse(P>0.05),the differences were not statistically significant.Conclusion:When soft markers on fetal ultrasonography are combined with structural abnormalities,the detection rate of fetal chromosomal abnormalities increases,when older women are combined with other prenatal diagnostic indications and when NIPT testing is high risk.The combined use of chromosomal microarray analysis and karyotyping in prenatal diagnosis can combine the advantages of both diagnostic modalities and improve the diagnosis rate of abnormal fetuses. |
PDF Full Text Request