Adverse pregnancy outcome in fetuses with early increased nuchal translucency: prospective cohort study

OBJECTIVES

An increased nuchal translucency (NT) ≥3.5mm is a well-established marker for congenital anomalies and adverse pregnancy outcome between 11 and 14 weeks of gestation. Little is known about its performance as a screening tool before 11 weeks of gestation. We aimed to investigate in a prospective setting whether fetuses with an increased NT before 11 weeks of gestation are at risk for an adverse pregnancy outcome.

METHODS

This is a prospective cohort study including pregnant women with a viable fetus with a NT≥2.5mm and a crown-rump-length (CRL) <45mm. All women were referred to our fetal medicine unit (FMU) and scheduled for a follow-up scan where the NT was remeasured after one week when the CRL was >45mm. Two groups were evaluated: cases with a normalized NT(<3.5mm) and cases with a persistently increased NT (≥3.5mm). We monitored the cases until four weeks after delivery. The main outcome was a composite adverse outcome of aneuploidies, other genetic disorders, structural anomalies and pregnancy loss. We performed subgroup analyses of NT thickness at inclusion and normalized or persistently increased NT at follow-up.

RESULTS

We included 109 cases of which 35.8% (39/109) had an adverse pregnancy outcome. Of these 64.1% (25/39) were aneuploidies which corresponds to 22.9% (25/109) aneuploidies in total. The subgroups of NT thickness at inclusion of 2.5-3.4, 3.5-4.4 and ≥4.5mm showed abnormal outcomes in 22.0% (9/41), 40.0% (18/45), 52.2% (12/23) respectively. In fetuses with a normalized NT and without ultrasound abnormalities at follow-up scan, the incidence of adverse outcome was 8.5% (5/59), of which 5.1% (3/59) were aneuploidies.

CONCLUSION

Fetuses with an early increased NT thickness are at considerable risk of an adverse pregnancy outcome, even if the NT normalizes after 11 weeks. Not all congenital anomalies can be diagnosed with routine first-trimester screening such as non-invasive prenatal testing and/or a first-trimester anomaly scan. Therefore, expectant parents should always be referred to a FMU for detailed ultrasonography. Invasive prenatal testing should be offered if an increased nuchal translucency of ≥2.5mm is observed before 11 weeks of gestation. This article is protected by copyright. All rights reserved.

Molecular Approaches in Fetal Malformations, Dynamic Anomalies and Soft Markers: Diagnostic Rates and Challenges-Systematic Review of the Literature and Meta-Analysis

Fetal malformations occur in 2-3% of pregnancies. They require invasive procedures for cytogenetics and molecular testing. "Structural anomalies" include non-transient anatomic alterations. "Soft markers" are often transient minor ultrasound findings. Anomalies not fitting these definitions are categorized as "dynamic". This meta-analysis aims to evaluate the diagnostic yield and the rates of variants of uncertain significance (VUSs) in fetuses undergoing molecular testing (chromosomal microarray (CMA), exome sequencing (ES), genome sequencing (WGS)) due to ultrasound findings. The CMA diagnostic yield was 2.15% in single soft markers (vs. 0.79% baseline risk), 3.44% in multiple soft markers, 3.66% in single structural anomalies and 8.57% in multiple structural anomalies. Rates for specific subcategories vary significantly. ES showed a diagnostic rate of 19.47%, reaching 27.47% in multiple structural anomalies. WGS data did not allow meta-analysis. In fetal structural anomalies, CMA is a first-tier test, but should be integrated with karyotype and parental segregations. In this class of fetuses, ES presents a very high incremental yield, with a significant VUSs burden, so we encourage its use in selected cases. Soft markers present heterogeneous CMA results from each other, some of them with risks comparable to structural anomalies, and would benefit from molecular analysis. The diagnostic rate of multiple soft markers poses a solid indication to CMA.

Chromosomal abnormalities detected by karyotyping and microarray analysis in twins with structural anomalies

OBJECTIVES

To evaluate the incidence and types of chromosomal abnormalities detected in twins with structural anomalies and compare their distribution according to chorionicity and amnionicity and by structural-anomaly type. The added value of chromosomal microarray analysis (CMA) over conventional karyotyping in twins was also estimated.

METHODS

This was a single-center, retrospective analysis of 534 twin pregnancies seen over an 11-year period, in which one or both fetuses were diagnosed with congenital structural anomalies on ultrasound. The ultrasound findings and invasive prenatal diagnostic results were reviewed. Twin pregnancies were categorized as monochorionic monoamniotic (MCMA), monochorionic diamniotic (MCDA) or dichorionic diamniotic (DCDA). Chromosomal abnormalities detected by G-banding karyotyping and/or CMA were analyzed by chorionicity and amnionicity and by structural-anomaly type.

RESULTS

The 534 twin pairs analyzed comprised 25 pairs of MCMA, 112 pairs of MCDA and 397 pairs of DCDA twins. Of the 549 fetuses affected by structural anomalies, 432 (78.7%) underwent invasive prenatal testing and cytogenetic results were obtained. The incidence of overall chromosomal abnormalities in the DCDA fetuses (25.4%) was higher than that in the MCMA (3.7%) and MCDA (15.3%) fetuses. The incidence of aneuploidy was significantly higher in the DCDA group (22.8%) than in the MCMA (0.0%) and MCDA (12.4%) groups. The incidence of chromosomal abnormalities detected in fetuses, with anomalies of the cardiovascular, faciocervical, musculoskeletal, genitourinary and gastrointestinal systems, was higher in the DCDA group than in the MCDA group. In both the DCDA and MCDA groups, hydrops fetalis was associated with the highest incidence of chromosomal abnormality; of these fetuses, 67.6% had Turner syndrome (45,X). Pathogenic copy-number variations (CNVs) undetectable by karyotyping were identified by CMA in five (2.0%; 95% CI, 0.3-3.7%) DCDA fetuses. No pathogenic CNVs were found in MCMA and MCDA twins.

CONCLUSIONS

Dichorionic twins with structural anomalies have a higher risk of chromosomal abnormalities, especially aneuploidies, than do monochorionic twins. The incremental diagnostic yield of CMA over karyotyping seems to be lower (2.0%) in twins than that reported in singleton pregnancy. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Effectiveness of 12-13-week scan for early diagnosis of fetal congenital anomalies in the cell-free DNA era

OBJECTIVES

The main aim of this study was to assess the proportion and type of congenital anomalies, both structural and chromosomal, that can be detected at an early scan performed at 12-13 weeks' gestation, compared with at the 20-week structural anomaly scan offered under the present screening policy. Secondary aims were to evaluate the incidence of false-positive findings and ultrasound markers at both scans, and parental choice regarding termination of pregnancy (TOP).

METHODS

Sonographers accredited for nuchal translucency (NT) measurement were asked to participate in the study after undergoing additional training to improve their skills in late first-trimester fetal anatomy examination. The early scans were performed according to a structured protocol, in six ultrasound practices and two referral centers in the north-east of The Netherlands. All women opting for the combined test (CT) or with an increased a-priori risk of fetal anomalies were offered a scan at 12-13 weeks' gestation (study group). All women with a continuing pregnancy were offered, as part of the 'usual care', a 20-week anomaly scan.

RESULTS

The study group consisted of 5237 women opting for the CT and 297 women with an increased a-priori risk of anomalies (total, 5534). In total, 51 structural and 34 chromosomal anomalies were detected prenatally in the study population, and 18 additional structural anomalies were detected after birth. Overall, 54/85 (63.5%) anomalies were detected at the early scan (23/51 (45.1%) structural and all chromosomal anomalies presenting with either an increased risk at first-trimester screening or structural anomalies (31/34)). All particularly severe anomalies were detected at the early scan (all cases of neural tube defect, omphalocele, megacystis, and multiple severe congenital and severe skeletal anomalies). NT was increased in 12/23 (52.2%) cases of structural anomaly detected at the early scan. Of the 12 cases of heart defects, four (33.3%) were detected at the early scan, five (41.7%) at the 20-week scan and three (25.0%) after birth. False-positive diagnoses at the early scan and at the 20-week scan occurred in 0.1% and 0.6% of cases, respectively, whereas ultrasound markers were detected in 1.4% and 3.0% of cases, respectively. After first- or second-trimester diagnosis of an anomaly, parents elected TOP in 83.3% and 25.8% of cases, respectively.

CONCLUSIONS

An early scan performed at 12-13 weeks' gestation by a competent sonographer can detect about half of the prenatally detectable structural anomalies and 100% of those expected to be detected at this stage. Particularly severe anomalies, often causing parents to choose TOP, are amenable to early diagnosis. The early scan is an essential part of modern pregnancy care. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Infantile hemangiomas and structural anomalies: PHACE and LUMBAR syndrome

In a subset of patients, infantile hemangiomas may be associated with structural anomalies. Structural anomalies may affect the upper body (PHACE Syndrome) or the lower body (LUMBAR Syndrome). Since their initial descriptions, improved understanding of these two syndromes has lead to recognition of a broader phenotypic spectrum than initially recognized. This paper aims to provide an updated review of the presentation, associated anomalies, and management of PHACE and LUMBAR syndromes, two well-characterized syndromes associated with IH.