Analysis of non-invasive Prenatal gene detection for pregnant women of advanced age

Objective To explore the screening efficiency of noninvasive prenatal gene testing (NIPT) for fetal chromosomal aneuploidy among pregnant women of advanced age.Methods A total of 2000 pregnant women who met the inclusion and exclusion criteria registered at the community health service center from April 28,2017 to December 30,2017 were included in the study,and received free NIPT. For those with high risk,further amniocentesis and fetal chromosome karyotype analysis were further carried out.Kappa test was used to analyze the consistency of NIPT and chromosome core analysis results. The sensitivity,specificity,positive predictive value and negative predictive value of NIPT were obtained.Results A total of 17 cases of fetal chromosomal abnormalities were detected among the blood samples of 2000 pregnant women. Ten of them were diagnosed as fetal chromosomal abnormalities by prenatal diagnosis such as amniocentesis (including 6 cases of 21-trisomy syndrome,2 cases of 18-Trisomy syndrome and 2 cases of sex chromosome abnormalities). The sensitivity and negative predictive value of NIPT to 21-trisomy syndrome,18-trisomy syndrome and sex chromosome abnormalities were all 100. 00%. The specificity were 99. 95%,100. 00%,and 99. 90%,respectively and the positive predictive value were 85. 71%,100. 00% and 50. 00%,respectively. The sensitivity and positive predictive value of NIPT to autosomal abnormalities was 0. Compared with fetal chromosome karyotype analysis,NIPT has a good consistency in the examination of 21-trisomy syndrome and 18-trisomy syndrome.Conclusion NIPT has good screening efficiency and is of great significance for the prevention and control of birth defects,so it is worth popularizing and implementing.