Chromosomal and genetic anomalies in fetuses with nuchal translucency between 3.0 and 3.4 mm: A systematic review and meta-analysis.
Arianna Carta, Lorenza Della Valle, Giuseppe Rizzo et al.
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In 30 seconds
This systematic review and random-effects meta-analysis assessed chromosomal and genetic findings in fetuses with nuchal translucency (NT) of 3.0–3.4 mm and the potential added yield of invasive testing over cfDNA. Seventeen studies included 7007 fetuses. Chromosomal anomalies were identified in 13.1% (95% CI 9.3-17.3); among fetuses with isolated NT in this range, the pooled rate was 12.4% (95% CI 7.9-17.7). Pathogenic or likely pathogenic copy number variants were reported in 2.5% (95% CI 1.3-3.9).
Key findings
- Chromosomal anomalies occurred in 13.1% (95% CI 9.3-17.3) of fetuses with NT of 3.0–3.4 mm.
- For isolated NT of 3.0–3.4 mm, the pooled rate of chromosomal anomalies was 12.4% (95% CI 7.9-17.7).
- Pathogenic or likely pathogenic copy number variants were found in 2.5% (95% CI 1.3-3.9).
- Single-gene disorders detected by NGS/WES were reported in 5.7% (95% CI 3.3-8) of cases.
Why it matters
These pooled estimates show that a modestly increased NT measurement can be associated with a range of chromosomal and genetic findings, including variants beyond common trisomies. The results help frame counselling about the scope of genetic findings and the potential limits of cfDNA screening, while the estimates should be interpreted in light of the included studies and testing approaches.
What to keep in mind
The estimates combine studies with differing assessment methods and populations; the abstract does not provide further detail on heterogeneity or study quality.