To analyze the detection effect of non-invasive prenatal testing (NIPT) on detecting fetal common chromosome aneuploidy abnormalities in Peking University Shenzhen Hospital, and to explore the correlation between different gestational weeks, maternal age and detection effect indicators.

Pregnant women who underwent NIPT and were with high risk result in Peking University Shenzhen Hospital from June 2013 to April 2019, were selected to analyze amniotic fluid chromosome karyotype, and others with low risk were followed-up by telephone. Basing on the chromosome karyotype results and follow-up results, the fetus was diagnosed and analyzed the NIPT detection effect index. According to the maternal age, they were divided into 4 groups: < 30 years old group, 30~34 years old group, 35~39 years old group, ≥ 40 years old group. According to the gestational age, they were divided into 4 groups: ≤13^{+ 6} weeks group, 14-22^{+ 6} weeks group, 23-27^{+ 6} weeks group, ≥ 28 weeks group. The correlation of sensitivity, specificity, positive predictive value and false positive rate with maternal age and gestational age were analyzed.

(1) A total of 43, 918 pregnant women with NIPT were included in the statistics. The overall sensitivity of NIPT was 100.00%, the specificity was 99.76% and the false positive rate was 0.24%.(2) The sensitivity and specificity of NIPT to T21, T18, T13, and sex chromosome abnormalities were all over 99% and the false positive rate was less than 0.5%. (3) In the advanced age group, there was a statistically significant difference in the specificity between the 35~39-year-old group and the 30~34-year-old group (P<0.05), and the differences in other screening indicators were not statistically significant. There was no statistically significant difference in the screening index comparison of grouped data during gestational week (P<0.05). (4) Among the false positive cases, it was found that 2 cases of newborns had congenital heart disease, 1 case with slight separation of double renal pelvis and 1 case with multiple abnormalities and other non-chromosomal abnormalities.

Non-invasive prenatal testing (NIPT) had high accuracy and specificity for common chromosome aneuploidy abnormalities, and low false positive rate, especially for trisomy 21. There is no significant difference in the detection effect of NIPT for pregnant women in different ages and different gestational weeks. For the cases with positive NIPT results, it was necessary to guard against the occurrence of fetal non-chromosome abnormalities and other abnormalities.