Clinical Application of Chromosomal Microarray Analysis in Pregnant Women with Advanced Maternal Age and Fetuses with Ultrasonographic Soft Markers

BACKGROUND: In pregnant women with advanced maternal age (AMA) and fetuses with ultrasonographic (USG) soft markers it is always challenging to decide whether to implement chromosomal microarray analysis (CMA) or not. It is unclear whether CMA should be used in the fetuses with isolated USG soft markers, and there is still a lack of extensive sample research. MATERIAL/METHODS: We enrolled 1521 cases in our research and divided them into 3 groups as follows: pregnant women with isolated AMA (group 1, n=633), pregnant women whose fetuses had isolated USG soft markers (group 2, n=750), and pregnant women with AMA whose fetuses had isolated USG soft markers (group 3, n=138). All pregnant women underwent prenatal ultrasound and amniocentesis, and fetal cells in the amniotic fluid were used for genetic analysis of CMA. All participants signed a written informed consent prior to CMA. RESULTS: Abnormal findings were detected by CMA in 330 (21.70%) fetuses, including 37 (2.43%) clinically significant copy number variations (CNVs), 52 (3.42%) benign or likely benign CNVs, and 240 (15.78%) variants of unknown significance. The frequency of clinically significant CNVs in group 1 and group 2 were significantly lower than that in group 3 (2.37% and 2.0% vs 5.07%, P<0.01). More than a half (59.46%, 22/37) of the pregnant women decided to continue their pregnancy despite having a fetus diagnosed with clinically significant CNV. CONCLUSIONS: CMA can increase the diagnostic yield of fetal chromosomal abnormality for pregnant women with isolated AMA or/and their fetuses had isolated USG soft markers.