The clinical performance of fetal sex chromosome abnormalities in serum biochemical screening in the second trimester.

This study aimed to investigate the serum biochemical markers' propensity associated with sex chromosome abnormalities (SCAs) and assess the clinical efficacy of SCAs in serum biochemical screening during the second trimester. A retrospective case-control analysis was conducted on pregnant women who underwent serum biochemical screening during the second trimester. The study compared groups of women with SCAs to those with normal chromosome karyotypes to assess changes in biochemical markers. We analysed and compared the performance of serum biochemical screening in each SCA group. The results showed that the alterations in serum biochemical markers varied among the different SCA groups. Typically, the serum biochemical markers of fetal SCAs were either above the 95th percentile or below the 5th percentile. The proportions of high- and intermediate-risk findings for 45,X, 47,XXX, 47,XXY, 47,XYY, and mosaic sex chromosomal abnormalities were 43.48%, 78.95%, 63.89%, 70.59%, and 78.13%, respectively. Besides detecting fetal trisomy 21 and trisomy 18, the current contingent screening procedures may also accidentally identify various fetal SCAs at a rate of 69.18%.