Beschreibung:
<jats:title>Abstract</jats:title><jats:sec><jats:title>Objective</jats:title><jats:p>To assess the outcomes of pregnancies at high‐risk for rare autosomal trisomies (RATs) and segmental imbalances (SIs) on cell‐free DNA (cfDNA) screening.</jats:p></jats:sec><jats:sec><jats:title>Method</jats:title><jats:p>A retrospective study of women who underwent cfDNA screening between September 2019 and July 2021 at three ultrasound services in Australia. Positive predictive values (PPVs) were calculated using fetal chromosomal analysis.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Among 23,857 women screened, there were 93 high‐risk results for RATs (0.39%) and 82 for SIs (0.34%). The PPVs were 3.8% (3/78, 95% CI 0.8%–10.8%) for RATs and 19.1% (13/68, 95% CI 10.6%–30.5%) for SIs. If fetuses with structural anomalies were also counted as true‐positive cases, the PPV for RATS increased to 8.5% (7/82, 95% CI 3.5%–16.8%). Among 85 discordant cases with birth outcomes available (65.4%), discordant positive RATs had a significantly higher proportion of infants born below the 10th and 3rd birthweight percentiles than expected (19.6% (<jats:italic>p</jats:italic> = 0.022) and 9.8% (<jats:italic>p</jats:italic> = 0.004), respectively), which was not observed in the SI group (2.9% < 10th (<jats:italic>p</jats:italic> = 0.168) and 0.0% <3rd (<jats:italic>p</jats:italic> = 0.305)).</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>The PPVs for SI and RAT results are low, except when a structural abnormality is also present. Discordant positive RATs are associated with growth restriction.</jats:p></jats:sec>