Late first-trimester ultrasound findings can alter management after high-risk NIPT result

Retrospective study on NIPT or NIPT plus combined with ultrasound in screening fetal chromosomal abnormalities

This retrospective study analyzed 306 pregnant women, with 182 undergoing genetic testing using NIPT plus and CMA, and 124 undergoing standard NIPT and CMA. The study aimed to compare the clinical performance of NIPT and NIPT plus in prenatal evaluation by using CMA as the gold standard to assess the diagnostic efficiency of the two screening methods. NIPT plus and NIPT results were correlated with ultrasound findings to evaluate their accuracy and clinical utility. The diagnostic performance of each method was compared against CMA to assess sensitivity, specificity, false positive and false negative rates, as well as positive predictive value and negative predictive value. The combined use of NIPT plus and ultrasound significantly improved the detection rate of sex chromosome aneuploidy (SCA), microdeletion/microduplication syndromes (MMS), and rare autosomal trisomies (RAT) compared to NIPT plus alone. Ultrasound combined with NIPT plus achieved the highest sensitivity (88.24%) for SCA/RAT/ MMS. However, NIPT plus exhibited a higher false positive rate compared to standard NIPT. In contrast, NIPT combined with ultrasound demonstrated the highest PPV (88.89%) for common trisomies (T13, T18, T21). False negatives were more prevalent in standard NIPT, particularly for SCA, MMS, and RAT, emphasizing its limitations for detecting complex chromosomal abnormalities. NIPT plus, when combined with ultrasound, offers significant improvements in the detection of rare chromosomal abnormalities like SCA, MMS, and RAT, while maintaining high detection rates for common trisomies. Although NIPT plus has a higher false positive rate, the inclusion of ultrasound enhances screening accuracy and clinical decision-making. This study supports the use of NIPT plus combined with ultrasound as the optimal screening strategy, particularly for rare and complex chromosomal abnormalities, while standard NIPT remains highly effective for screening common trisomies.

Antenatal reproductive screening for pregnant people including preconception: Provides the best reproductive opportunity for informed consent, quality, and safety

INTRODUCTION

This antenatal screening review will include reproductive screening evidence and approaches for pre-conception and post-conception, using first to third trimester screening opportunities.

METHODS

Focused antenatal screening peer-reviewed publications were evaluated and summarized.

RESULTS

Evidenced-based reproductive antenatal screening elements should be offered and discussed, with the pregnancy planning or pregnant person, during Preconception (genetic carrier screening for reproductive partners, personal and family (including reproductive partner) history review for increased genetic and pregnancy morbidity risks); First Trimester (fetal dating with ultrasound; fetal aneuploidy screening plus consideration for expanded fetal morbidity criteria, if appropriate; pregnant person preeclampsia screening; early fetal anatomy screening; early fetal cardiac screening); Second Trimester for standard fetal anatomy screening (18-22 weeks) including cardiac; pregnant person placental and cord pathology screening; pregnant person preterm birth screening with cervical length measurement); Third Trimester (fetal growth surveillance; continued preterm birth risk surveillance).

CONCLUSION

Antenatal reproductive screening has multiple elements, is complex, is time-consuming, and requires the use of pre- and post-testing counselling for most screening elements. The use of preconception and trimesters 'one to three' requires clear patient understanding and buy-in. Informed consent and knowledge transfer is a main goal for antenatal reproductive screening approaches.

Importance of a detailed anomaly scan after a cfDNA test indicating fetal trisomy 21, 18 or 13

OBJECTIVE

To investigate the effect of the presence or absence of fetal anomalies and soft markers diagnosed by ultrasound on positive predictive value (PPV) 21, 18 and 13 in pregnancies with a high-risk cfDNA result.

METHODS

Retrospective study including singleton pregnancies with high-risk NIPT results for common trisomies followed by invasive testing. The cases were grouped by gestational age at the time of invasive testing and by the presence or absence of fetal abnormalities or soft markers. The ultrasound was considered abnormal if at least one major defect or a soft marker was detected.

RESULTS

A total of 173 women were included. Median maternal and gestational age was 37.7 years and 14.0 weeks, respectively. CfDNA test result showed high-risk for trisomy 21 and trisomy 18 or 13 in 119 and 54 cases, respectively. The "pre-ultrasound" PPV for trisomy 21 and for trisomy 18 or 13 were 98.3% and 68.4%, respectively. In case of a high-risk result for trisomy 21 and no fetal anomalies, the PPV was 86.7% while it was 100% if there were anomalies or markers present. In the case of a high-risk result for trisomy 18 or 13, the PPV was 9.5% if the ultrasound examination was normal and 100% if the ultrasound examination was abnormal.

CONCLUSION

This study suggests that a detailed ultrasound examination performed after a cfDNA result that is high-risk for one of the common autosomal trisomies adds significantly to establishing an individualized risk assessment. This is particularly true in cases with a high-risk result for trisomies 18 or 13.

First-Trimester Ultrasound Screening in Routine Obstetric Practice

Technologic advances and ultrasonographer-physician experience in fetal imaging have led to significant improvements in our ability to distinguish between normal and abnormal fetal structural development in the latter part of the first trimester. As a critical component of pregnancy care, assessment of fetal anatomy at the end of the first trimester with a standardized imaging protocol should be offered to all pregnant patients regardless of aneuploidy screening results because it has been demonstrated to identify approximately half of fetal structural malformations. Early identification of abnormalities allows focused genetic counseling, timely diagnostic testing, and subspecialist consultation. In addition, a normal ultrasound examination result offers some degree of reassurance to most patients. Use of cell-free DNA alone for aneuploidy screening while foregoing an accompanying early anatomic evaluation of the fetus will result in many anomalies that are typically detected in the first trimester not being identified until later in pregnancy, thus potentially diminishing the quality of obstetric care for pregnant individuals and possibly limiting their reproductive options, including pregnancy termination.

Molecular Point-of-Care Assay Development: Design and Considerations

Molecular diagnostic point-of-care (MDx POC) testing is gaining momentum and is increasingly important for infectious disease detection and monitoring, as well as other diagnostic areas such as oncology. Molecular testing has traditionally required high-complexity laboratories. Laboratory testing complexity is determined by utilizing the Clinical Laboratory Improvement Amendments of 1988 (CLIA) Categorization Criteria scorecard, utilizing seven criteria that are scored on a scale of one to three. Previously, most commercially available point-of-care (POC) tests use other analytes and technologies that were not found to be highly complex by the CLIA scoring system. However, during the COVID-19 pandemic, MDx POC testing became much more prominent. Utilization during the COVID-19 pandemic has demonstrated that MDx POC testing applications can have outstanding advantages compared to available non-molecular POC diagnostic tests. This article introduces MDx POC testing to students, technologists, researchers, and others, providing a general algorithm for MDx POC test development. This algorithm is an introductory, step-by-step decision tree for defining a molecular POC diagnostic device meeting the functional requirements for a desired application. The technical considerations driving the decision-making include nucleic acid selection method (DNA, RNA), extraction methods, sample preparation, number of targets, amplification technology, and detection method. The scope of this article includes neither higher-order multiplexing, nor quantitative molecular analysis. This article covers key application considerations, such as sensitivity, specificity, turnaround time, and shipping/storage requirements. This article provides an overall understanding of the best resources and practices to use when developing a MDx POC assay that may be a helpful resource for readers without extensive molecular testing experience as well as for those who are already familiar with molecular testing who want to increase MDx availability at the POC. © 2024 Wiley Periodicals LLC.

Role of late first-trimester ultrasound in women with a positive NIPT result

This Correspondence comments on Scott et al. Click here to view the article.