Impact of introducing cell‐free DNA screening into clinical care on first trimester ultrasound

Objective First‐trimester ultrasound is an important component of prenatal care. We investigated the impact of introducing cell‐free DNA (cfDNA) aneuploidy screening into routine care, on performance of first‐trimester ultrasound. Methods Retrospective study of patients who had prenatal care at a tertiary referral center. We compared the performance of any first‐trimester ultrasound between three different aneuploidy screening protocols, used consecutively during the study period: (1) combined first‐trimester screening (FTS); (2) FTS and cfDNA offered together; (3) patients requested to choose between FTS and cfDNA. Secondary outcomes included performance of nuchal translucency (NT), aneuploidy screens and diagnostic genetic procedures. Results The number of patients undergoing first‐trimester ultrasound remained similar with the second protocol but decreased in the third (68.7% vs. 40.9%, OR 0.32, 95% CI 0.25–0.4, p