Application of Chromosomal Karyotype Analysis Combined With Chromosomal Microarray Analysis in the Amniotic Fluid of Advanced Maternal Age

Objective

To explore the application and value of chromosomal karyotype analysis combined with Chromosomal Microarray Analysis (CMA) in the amniotic fluid of advanced maternal age.

Methods

A total of 817 advanced maternal age (AMA) who underwent amniocentesis at the Prenatal Diagnosis Center of Huizhou Central People's Hospital between January 2018 and July 2024 were enrolled in this study. The women were grouped based on different age ranges and prenatal diagnosis factors. These groups were used to compare the detection rates and differences between chromosomal karyotype analysis and CMA.

Result

The overall chromosomal abnormality rates detected by karyotype analysis in the 35–39 years age group and the ≥ 40 years age group were 8.81% and 13.79%, respectively, with a statistically significant difference (p < 0.05). For CMA, the overall abnormality rates in the same age groups were 10.79% and 15.33%, respectively, but the difference was not statistically significant (p > 0.05). The non-solely advanced-age group (those with additional factors beyond just advanced age) had higher overall chromosomal abnormality rates, aneuploidy rates, structural abnormality rates, and mosaicism rates compared to the solely advanced-age group, with statistically significant differences (p < 0.05). Additionally, the non-solely advanced-age group had a higher overall abnormality rate detected by CMA compared to the solely advanced-age group, with a statistically significant difference (p < 0.05). However, there were no statistically significant differences between the two groups in terms of the detection of pathogenic, likely pathogenic, and variants of uncertain significance (p > 0.05). In this study, a total of 68 cases were identified where the results of karyotype analysis and CMA were inconsistent.

Conclusion

The overall abnormal rate of chromosomal karyotype analysis increases with maternal age, while the overall abnormal rate of CMA shows no significant correlation with maternal age. The abnormal rates are significantly higher in AMA with additional factors. The combination of chromosomal karyotype analysis and CMA can validate and complement each other, thereby improving the detection rates of chromosomal abnormalities in amniotic fluid samples of AMA. This provides a diagnostic basis for subsequent pregnancy choices, which effectively reduces the birth of fetuses with chromosomal abnormalities and enhances population quality.