A new contingent screening strategy increased detection rate of trisomy 21 in the first trimester

• Published in: BMC pregnancy and childbirth Vol. 23; no. 1; pp. 1 - 791
• Main Authors: Luo, Wei, He, Bin, Han, Daiwen, Yuan, Lixing, Tang, Jun, Pang, Ling, Zou, Fene, Zhao, Kai, Liu, Shanling, Hu, Ting
• Format: Journal Article
• Language: English
• Published: London BioMed Central 14.11.2023; BMC
• Subjects: Amniocentesis; Chromosomes; Contingent screening strategy; Developing countries; Diabetes; Down syndrome; First-trimester screening; Gestational age; LDCs; Medical diagnosis; Non-invasive prenatal screening; Pregnancy; Prenatal diagnosis; Serum biochemical screening; Software; Trisomy 21; Womens health; United States > US; China
• ISSN: 1471-2393; 1471-2393
• DOI: 10.1186/s12884-023-06115-1

Abstract Background Although the traditional contingent screening strategy is effective, there are still undetected low-risk trisomy 21. This study aims to define appropriate cut-off values of serum biochemical markers at low-risk and develop a strategy for sequential prenatal testing associated with first-trimester screening to increase the detection rate of trisomy 21. Methods This was a 9-year retrospective analysis of singleton pregnant women who underwent serum biochemical screening or combined first-trimester screening (CFTS) in the first trimester. For the low-risk group, the cut-off values of the serum biochemical markers were adjusted to determine the appropriate detection efficiency. Gravidas with abnormal serum biochemical markers at low-risk were advised to undergo further non-invasive prenatal screening (NIPS), whereas others continued with routine prenatal care. Results When cut-off values of free beta subunit of human chorionic gonadotropin (free β-hCG) multiples of the median (MoM) or pregnancy-associated plasma protein A (PAPP-A) MoM were defined with ≥ 2.75 or ≤ 0.5, 7.72% (2,194/28,405) in the serum biochemical screening group and 12.36% (4,005/32,403) in CFTS group could be detected as abnormal results for further NIPS. Finally, 55.56% (5/9) and 85.71% (6/7) of trisomy 21 cases with false-negative results were detected, and the overall detection rate for trisomy 21 was improved by 10.64% (5/47) and 12.77% (6/47), respectively. Conclusions The new contingent screening strategy can increase the detection rate of trisomy 21 compared with the traditional contingent screening strategy.