J Genet Med.  2018 Dec;15(2):79-86. 10.5734/JGM.2018.15.2.79.

The clinical usefulness of non-invasive prenatal testing in pregnancies with abnormal ultrasound findings

• Boo H
• Kim SY
• Seoung ES
• Kim MH
• Kim MY
• Ryu HM
• Han YJ
• Chung JH

• KMID: 2435946
• DOI: http://doi.org/10.5734/JGM.2018.15.2.79

Abstract

PURPOSE
This study aimed to evaluate the clinical usefulness of non-invasive prenatal testing (NIPT) as an alternative testing of invasive diagnostic testing in pregnancies with ultrasound abnormalities.
MATERIALS AND METHODS
This was a retrospective study of pregnant women with abnormal ultrasound findings before 24 weeks of gestation between April 2016 and March 2017. Abnormal ultrasound findings included isolated increased nuchal translucency, structural anomalies, and soft markers. The NIPT or diagnostic test was conducted and NIPT detected trisomy 21 (T21), T18, T13 and sex chromosomal abnormalities. We analyzed the false positive and residual risks of NIPT based on the ultrasound findings.
RESULTS
During the study period, 824 pregnant women had abnormal ultrasound findings. Among the study population, 139 patients (16.9%) underwent NIPT. When NIPT was solely performed in the patients with abnormal ultrasound findings, overall false positive risk was 2.2% and this study found residual risks of NIPT. However, the discordant results of NIPT differed according to the type of abnormal ultrasound findings. Discordant results were significant in the group with structural anomalies with 4.4% false positive rate. However, no discordant results were found in the group with single soft markers.
CONCLUSION
This study found different efficacy of NIPT according to the ultrasound findings. The results emphasize the importance of individualized counseling for prenatal screening or diagnostic test based on the type of abnormal ultrasound.

Keyword

Non-invasive prenatal test; Cell-free nucleic acids; Prenatal diagnosis; Ultrasonography; Congenital abnormalities

MeSH Terms

Chromosome Aberrations
Congenital Abnormalities
Counseling
Diagnostic Tests, Routine
Down Syndrome
Female
Humans
Nuchal Translucency Measurement
Pregnancy*
Pregnant Women
Prenatal Diagnosis
Retrospective Studies
Ultrasonography*