Soft markers for aneuploidy following reassuring first trimester screening: what should be done?

The likelihood of detecting abnormal karyotypes in fetuses with a single major anomaly or "soft" marker on ultrasonographic scanning

OBJECTIVE

Fetuses with abnormal karyotypes often exhibit distinctive ultrasonographic markers, including major anomalies and "soft" markers, indicating potential chromosomal issues. A crucial consideration arises when a single fetal anomaly is detected, raising the question of whether karyotyping is warranted, given the associated procedural risks. Our objective was to establish correlations between single fetal anomalies identified through ultrasound and chromosomal abnormalities.

METHODS

A cross-sectional study analyzed the karyotype of 1493 fetuses and detected a single ultrasonographic anomaly over a 16-year period. Karyotyping was performed using the standard karyotype technique. Moreover, data regarding the type of anomaly detected ultrasonographically, karyotype results, and outcomes following interventions were collected. Among other methods, the use of positive likelihood ratios (LR+) was used to evaluate the diagnostic accuracy of ultrasound compared to karyotyping.

RESULTS

In total, an aberrant karyotype was identified in 99 fetuses (6.6%). This was most commonly observed in cases involving a "soft" marker, occurring in 27 out of 218 fetuses (12.4%). The most frequently detected aberrant karyotype resulted from aneuploidies (80.6% of cases), notably trisomy 21 (50.5%). "Soft" markers predicted chromosomal issues (LR+ = 1.9; OR = 2.4), and isolated polyhydramnios (LR+ = 1.54; OR = 1.6) showed significance in predicting fetal chromosomal aberrations.

CONCLUSION

When assessing the necessity for karyotyping in fetuses with single major anomalies or "soft" markers, it is crucial to consider individual risks for chromosomopathies, including the LR+ of the detected marker. In cases where fetuses exhibit isolated anomalies with a normal karyotype, additional diagnostic measures, such as molecular cytogenetic and molecular genetics techniques, may become necessary.

Effectiveness of Chromosomal Microarray Analysis for Prenatal Diagnosis of Fetal Echogenic Intracardiac Focus: A Single-Center Experience

BACKGROUND

Echogenic intracardiac focus (EIF) is a common ultrasound finding during pregnancy. However, the correlation between fetal EIF and cardiac abnormality remains in dispute until now. The study aimed to examine the association of fetal EIF with chromosomal abnormality by means of chromosomal microarray analysis (CMA).

MATERIALS AND METHODS

A total of 192 pregnant women with fetal EIF undergoing amniocentesis or umbilical cord blood puncture were recruited and assigned into groups A (8 cases with isolated EIF alone), B (75 cases with EIF and other cardiac malformations) and C (109 cases with EIF and extracardiac malformations). All fetuses underwent karyotyping analysis and CMA simultaneously. The detection of chromosomal abnormality and copy number variations (CNVs) were compared.

RESULTS

Chromosomal karyotyping identified 5 fetuses with chromosomal abnormality, including 3 cases with trisomy 21, one fetus with Turner's syndrome, and one fetus with chromosome 8 mosaicism, while CMA detected 6 additional fetuses with CNVs, including 2 fetuses with pathogenic CNVs and 4 fetuses with variants of uncertain significance (VOUS). There was no significant difference among groups A (0), B (5.33%) and C (6.42%) in terms of the prevalence of chromosomal abnormality (P> 0.05). Among the 4 fetuses with VOUS, pregnancy continued in 2 fetuses, and pregnancy was terminated in other 2 fetuses.

CONCLUSION

An isolated EIF may not correlate with chromosomal abnormality. However, CMA is recommended in fetuses with CMA complicated by other abnormal cardiac ultrasound findings, which facilitates the prediction of fetal outcomes during the genetic counseling and precision assessment of prognosis.

ACR Appropriateness Criteria® Second and Third Trimester Screening for Fetal Anomaly

The Appropriateness Criteria for the imaging screening of second and third trimester fetuses for anomalies are presented for fetuses that are low risk, high risk, have had soft markers detected on ultrasound, and have had major anomalies detected on ultrasound. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The importance of pre- and post-test counseling for prenatal cell-free DNA screening for common fetal aneuploidies

INTRODUCTION

Prenatal cell-free DNA screening for common fetal aneuploidies has rapidly changed the paradigm of prenatal care. Despite its advantages compared to conventional screening methods, its unexpectedly rapid implementation in clinical practice has generated several ethical and medical issues and misconceptions. Aggressive commercial marketing of cell-free DNA screening and media dissemination of misleading information have added confusion. Areas covered: This review provides an extensive update and will focus on the importance of pre-and post-test counseling for prenatal cell-free DNA screening not previously discussed extensively in the available literature. Additionally, we report cell-free DNA screening implementation in the largest obstetrical tertiary unit in Finland which is one of few countries that provides all prenatal screening methods free of charge for all women and has a very high uptake of first-trimester screening. This is not a systematical review, but rather a narrative overview which includes the most relevant and recent original publications and reviews covering this issue. Expert opinion: Despite being the most accurate method for screening of common fetal aneuploidies, the knowledge and counseling should be substantially improved. Cell-free DNA screening is not a replacement for diagnostic testing and its use in prenatal testing is complex and limited.

Long-Term Outcome of Fetuses with Soft Marker and Without Genetic or Structural Abnormality

Purpose

To determine long-term outcome of infants with isolated or multiple soft markers but no structural or chromosomal abnormalities.

Methods

A retrospective study of 78 pregnant women who were referred for amniocentesis and found to have soft markers including echogenic intracardiac focus/foci (EIF), echogenic bowel (EB), unilateral or bilateral choroid plexus cysts, (UCPCs or BCPCs) mild pyelectasis and single umbilical artery but no structural anomalies and outcomes of the liveborns with a 4- to 9-year follow-up was conducted.

Results

Among 28 fetuses with EIF, allergic asthma and epilepsy were diagnosed in two liveborns. We followed up nine pregnancies with EB, epilepsy was present in one case. Allergic asthma was detected in both UCPCs and BCPCs, whereas epilepsy and attention-deficit/hyperactivity disorder (ADHD) were diagnosed in two liveborns with BCPCs. Twelve liveborns with multiple soft markers were evaluated; no pathology was detected in most of them except one case of allergic asthma, one case of hearing impairment and one case of ADHD.

Conclusions

This study shows longer-term favorable outcomes of the liveborns with isolated or multiple soft markers without any aneuploidy and may provide insight into this debated point.