Methods From January 2018 to September 2021, a total of 1 000 cases of pregnant women who underwent amniocentesis in Affiliated Hospital of Inner Mongolia Medical University, were enrolled into this study. The clinical data were analyzed by retrospective analysis method. Binary logistic regression analysis was conducted to investigate the correlation between common prenatal screening indexes and fetal chromosomal aneuploidy. Receiver operating characteristic (ROC) curves were used to evaluate the predictive value of single and combined tests such as maternal serum screening tests, fetal ultrasonic soft indexes, noninvasive prenatal testing (NIPT) for screening fetal chromosomal abnormalities. The procedure followed in this study was approved by the Ethics Committee of our hospital (Approval No. YKD2016108). Informed concents were obtained from all participants.
Results ① The total rate of fetal chromosomal abnormalities in this study was 14.0% (140/1 000). Among them, the abnormal rates of chromosome number, chromosome structure, and other types of chromosome abnormal were 72.9%, 18.6% and 8.6%, respectively. ② The results of binary logistic regression analysis showed that maternal serum screening tests showed high risk for trisomy 21 and trisomy 18 (OR=3.030, 10.094), fetal ultrasonic soft index abnormalities, structural abnormalities (OR=6.125, 3.774), and NIPT showed high risk for trisomy 21, trisomy 18, trisomy 13 and sex chromosomal abnormalities (OR=877.846, 29.111, 37.651, 43.514) were all related to fetal chromosomal aneuploidy (P<0.05). ③ The positive predictive values of NIPT combined with advanced pregnancy, maternal serum screening tests, and fetal ultrasonic soft indexes, respectively, for screening fetal chromosomal abnormalities were 52.5% (31/59), 44.8% (13/29) and 75.0% (6/8), respectively, which were respectively higher than those of 4.7% (8/172) of advanced pregnancy alone, 5.5% (15/273) of maternal serum screening tests alone, and 10.1% (20/198) of fetal ultrasonic soft indexes alone, and the differences were statistically significant (χ2=71.80, 48.21, 23.78; all with P<0.001). ④ The analysis of ROC curve results showed that the area under curve (AUC) and sensitivity of screening fetal chromosomal abnormalities in the advanced pregnancy combined with NIPT were higher than those in the advanced pregnancy, and the differences were statistically significant (P<0.05). To the fetal ultrasonic soft indexes combined with NIPT screening for fetal chromosomal abnormalities, the AUC was higher than that of fetal ultrasonic soft indexes alone, the specificity was higher than that of NIPT alone, and the differences were statistically significant (P<0.05). There were no significant differences between maternal serum screening tests combined with NIPT and one of them alone in AUC, sensitivity and specificity (P>0.05).
Conclusions Advanced pregnancy combined with NIPT can effectively reduce the use of interventional prenatal diagnosis. Maternal serum screening tests combined with NIPT can reduce the cost of screening fetal chromosomal abnormalities. Fetal ultrasonic soft indexes combined with NIPT has the best efficiency in diagnosing fetal chromosomal abnormalities.