Leiomyomas as a probable cause of false-positive result in non-invasive prenatal testing: a case report
Medical Review (Med. pregled), 2025, 61(3), 48-53.
K. Kercheva1,2, I. Bradinova1,3, G. Stancheva4,5, V. Peycheva4,5, R. Vazharova7, V. Dimitrova3,6
1 National Genetic Laboratory, University Specialized Hospital for Obstetrics and Gynecology “Maichin dom” – Sofia
2 Department “Medical Chemistry and Biochemistry”, Medical Faculty, Medical University – Sofia
3 Department “Obstetrics and Gynecology”, Medical Faculty, Medical University – Sofia
4 Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical University – Sofia
5 Laboratory of Genomic Diagnostics, Department of Medical Chemistry and Biochemistry, Medical University – Sofia
6 Clinic of „Pregnancy Pathology“, University Specialized Hospital for Obstetrics and Gynecology „Maichin Dom“ – Sofia
7 Department of „Biology, Medical Genetics, and Microbiology,“ Faculty of Medicine, Sofia University „Sv. Kliment Ohridski“
Abstract. Leiomyomas, or uterine fibroids, are benign smooth muscle tumors that com-monly affect women of reproductive age. In most cases, leiomyomas are asymptomatic during pregnancy. However, their presence is associated with an increased risk of obstetric complications and a higher likelihood of false-positive results in non-invasive prenatal testing (NIPT) for rare autosomal ane¬uploidies and submicroscopic chromosomal aberrations. We report the case of a 40-year-old primigravida with a spontaneously conceived pregnancy and no structural fetal anomalies at 12 weeks of gestation. Ultrasound examination revealed a large intramural/subserosal fibroid. Due to advanced maternal age, whole-genome sequencing-based NIPT was performed, which identified a high risk for deletions on chromosome 8, including a 19Mb deletion on the short arm (del8p12-p22) and a 3.5Mb deletion on the long arm (del8q11.21-q11.23). Following genetic counseling, the patient underwent amniocentesis, and sub¬sequent karyotyping and chromosomal microarray analysis confirmed a normal male karyotype (46,XY) and excluded the presence of chromosomal deletions or pathogenic copy number variants. The expanding scope of NIPT inevitably increases the frequency of false-positive or uninterpretable results, underscor¬ing the need for confirmatory invasive diagnostic testing and specialized ge¬netic counseling. High-risk NIPT findings in the context of maternal fibroids, par¬ticularly in the absence of ultrasound markers of chromosomal abnormalities, should be interpreted with caution and verified with invasive testing.
Key words: uterine fibroids, non-invasive prenatal testing, high risk pregnancy