False Positive Results in High-Risk Pregnancy for Chromosomal Anomalies: Psychological Considerations

Background: With a high sensitivity and specificity, non-invasive prenatal testing (NIPT) is an incomparable screening test for fetal aneuploidy. However, the method is rather newly introduced, and experiences with false positive results are few. Even rare cases of discordant results may cause psychological stress.

Aim of the Study: The aim of this study was to examine false positive cases of NIPT tests in high-risk pregnancies. The literature review was also performed to review psychological consequences of discordant results.

Materials and Methods: A retrospective study was conducted between 2015 and 2022. The Natera Panorama test was used to analyse the risk of trisomies 21 (Down syndrome), 18 (Edwars syndrome), 13 (Patau syndrome), X monosomy (Terner syndrome) and other sex chromosome abnormalities. High risk result of NIPT for aneuploidy was confirmed by the invasive testing.

Results: 2000 women with a singleton pregnancy participated in the study. Out of 2000 NIPT tests 22 cases with high risk results for chromosomal anomalies were detected. Only one false positive case with high risk result for trisomy 21 was detected. The overall positive predictive value (PPV) of NIPT for trisomies 21, 13, 18, X monosomy and XYY syndrome was 95%.

Conclusion: Our study has showed only one case with false positive result for trisomy 21. However these cases with discordant results are very sensitive from bioethical point of view. So such couples need further follow up and sometimes even psychological counselling. NIPT due to its high PPV significantly reduces the need for an invasive testing, thereby reducing the risk of miscarriage.