Screening Positive for Rare Autosomal Aneuploidies Increases Frequency of Adverse Pregnancy Outcomes and Alters Clinical Management.

objectiveOutcomes in pregnancies with rare autosomal aneuploidies (RAAs) are poorly characterized, with most studies having small sample sizes. Here, we describe outcomes and management in a large cohort of pregnancies that screened positive for an RAA (RAA+).

methodsResults of prenatal cell-free DNA screening were linked to de-identified insurance claims data. Diagnosis and procedure codes were used to estimate pregnancy outcomes and management. Relevant covariates in comparative analyses were adjusted using propensity-score matching. Outcomes were statistically compared using Mantel-Haenszel and McNemar's tests.

resultsAmong 682 RAA+ pregnancies, the rate of live birth was significantly lower (56.7% vs. 78.7%; p < 0.001), and the rates of miscarriage and preterm birth were significantly higher (14.8% vs. 3.2%, p < 0.001; 18.5% vs. 8.9%, p < 0.001; respectively), compared to pregnancies with RAA- results. In pregnancies that screened positive for a rare autosomal trisomy (RAT+) and in which the RAT+ results were known, ultrasounds (mean: 3.7 vs. 2.5, p = 0.002), and pregnancy-specific visits (mean: 6.6 vs. 5.1; p = 0.007) were more frequent compared with pregnancies in which the RAT+ result was unknown.

conclusionPregnancies with RAA+ results had higher rates of adverse outcomes compared with those with RAA- results, and awareness of RAA+ results was associated with more intensive monitoring.