Comparison of conventional karyotype analysis and CMA results with ultrasound findings in pregnancies with normal QF-PCR results.

Objective: In cases requiring fetal diagnostic testing, conventional karyotype analysis is initially preferred. However, quantitative fluorescent-polymerase chain reaction (QF-PCR) or fluorescent in situ hybridization methods are used alongside conventional karyotype analysis to obtain rapid results. If results cannot be obtained from conventional karyotype analysis, chromosomal microarray analysis (CMA) is a reasonable option in necessary cases. In this study, we analyzed the conventional karyotype and CMA results from pregnancies reported as having normal karyotypes by QF-PCR and assessed their correlation with ultrasound imaging results.

Materials and methods: Between 2020 and 2023, pregnant women with fetal structural anomalies detected by ultrasound and magnetic resonance imaging at the Eskişehir City Hospital, Clinic of Perinatology were referred to our prenatal diagnosis center. In samples obtained using appropriate diagnostic methods, QR-PCR and conventional karyotype analysis were performed initially. Pregnancies with chromosomal anomalies detected by QF-PCR were excluded from the study. For pregnancies with normal karyotypes, CMA was applied.

Results: In 203 pregnancies with a normal karyotype result from QF-PCR, 202 (99.5%) were reported as normal in conventional karyotype analysis, while 1 (0.5%) case showed deletion of chromosome 7. Among the remaining pregnancies, CMA examination revealed abnormal karyotype results in 25 (12.3%) cases. A relationship was found only between ventriculomegaly detected by ultrasound and CMA results. The prevalence of ventriculomegaly was higher in those with CMA abnormalities (16%) compared to those with normal CMA (4.5%), and this difference was statistically significant (p=0.045).

Conclusion: The benefit of CMA analysis in detecting chromosomal anomalies such as copy number variations, especially in cases reported as having a normal karyotype by QF-PCR and karyotype analysis, is evident. To evaluate the relationship between ultrasound anomalies and CMA results, each community should assess its own results.