Diagnostic differences between patients opting for non-invasive prenatal testing and patients having traditional prenatal diagnosis.

OBJECTIVE

To analyze possible missed chromosomal aberrations by utilization of cell-free fetal DNA (cffDNA) testing.

METHODS

A retrospective study of two cohorts who underwent amniocentesis or cffDNA testing was conducted. A total of 15,220 patients were included in amniocentesis group and 9,821 patients in cffDNA group. Part of the cffDNA group was followed up and informed of the results of invasive prenatal diagnosis. Chromosomal aberrations of amniocentesis group were classified according to the testing range of cffDNA testing and compared to the cffDNA group.

RESULTS

Chromosomal aberration rates in the two groups were 6.52% (992/15220) and 0.58% (57/9821), respectively. 3.75% (all patients), 3.33% (advanced maternal age), or 3.4% (positive results of serum screening) chromosome aberrations would have been missed since they exceeded the cffDNA range. Pathogenic chromosomal aberrations beyond the cffDNA testing range were estimated as 0.81%, 0.62% and 0.78% in the above three categories in amniocentesis group. Furthermore, unclear pathogenic chromosomal aberrations could be missed approximately by 1.01%, 0.92% and 0.97% in the corresponding categories in the amniocentesis group.

CONCLUSION

With the availability of cffDNA testing, an increasing number of patients tend to refuse invasive prenatal diagnosis. This may lead to missed diagnosis of chromosomal aberrations during prenatal screening.