Structural Fetal Anomalies Identified During First-Trimester Screening: A Single-Centre Experience in Romania

Background and Objectives: The 11-13⁺⁶-week scan has evolved from a nuchal translucency (NT) measurement into an early anatomical survey, and the anomalies it identifies increasingly shape prenatal counselling and management. Data from Central and Eastern European screening populations are scarce. Materials and Methods: Retrospective cohort of all pregnancies undergoing first-trimester combined screening in a single fetal medicine centre in Romania between August 2009 and April 2026, with a crown-rump length of 45-84 mm. The centre provides routine screening but also receives women referred after an abnormal finding elsewhere; the cohort is therefore described as a screening population with referral enrichment. Structural anomalies recorded prospectively in the ultrasound database at the first-trimester scan were classified by organ system and by first-trimester detectability category. NT, combined risk, karyotype and pregnancy outcome were extracted from the same database. Associations were quantified with odds ratios (OR) from logistic regression with cluster-robust standard errors by woman. Results: 11,229 pregnancies (10,015 women; 408 multiple pregnancies) were included. A structural anomaly was identified at 11-13⁺⁶ weeks in 197 (17.5 per 1000; 95% CI 15.3-20.1); 16.1 per 1000 (13.8-18.7) after exclusion of the years 2009-2012 and 16.9 per 1000 (14.6-19.5) in singleton pregnancies. A further 44 pregnancies had isolated cystic hygroma/hydrops or soft markers only. Cardiac defects (81; 7.2 per 1000) and abdominal-wall defects (74; 6.6 per 1000, of which 67 exomphalos) were present in 145 pregnancies (74%), followed by central nervous system (27), facial (23), skeletal (23), thoracic (10) and urogenital (10) anomalies; 37 pregnancies (19%) had anomalies in two or more systems. NT ≥ 3.5 mm was present in 59/197 (30%) anomalous versus 203/11,032 (1.8%) non-anomalous pregnancies (OR 22.8, 95% CI 16.3-31.9), and in 51% of cardiac defects. Among 37 karyotyped fetuses, 15 (41%) had a chromosomal abnormality. Pregnancy outcome was known for 87 anomalous pregnancies: 46 terminations, 33 live births and 8 fetal or neonatal deaths; 17 of 30 exomphalos cases with known outcome were live-born. Conclusions: In a screening population with referral enrichment, about 1 in 57 pregnancies had a structural anomaly identified at the 11-13⁺⁶-week scan, dominated by cardiac and abdominal-wall defects; the figure describes prenatally identified anomalies in this setting and is not a population-based prevalence. One third of these fetuses had increased NT and a high proportion of those tested had an abnormal karyotype, supporting the integration of systematic anatomical assessment and genetic evaluation into first-trimester screening.