Abstract
ABSTRACT
This study evaluated the association between first‐trimester ultrasound abnormalities and prenatal test selection within a centralized genetic counseling system in Japan. Advances in ultrasound screening and the increasing use of non‐invasive prenatal testing (NIPT) have expanded prenatal testing options, increasing the complexity of test selection in pregnancies with abnormal ultrasound findings. This retrospective cohort study included 87 pregnant women referred for genetic counseling because of abnormal first‐trimester ultrasound findings between July 2022 and December 2025. All patients received standardized prenatal genetic counseling. Clinical data were extracted from the medical records, and factors associated with the selection of invasive diagnostic testing were analyzed using multivariable logistic regression. Amniocentesis was selected in 41 pregnancies (47.1%), NIPT in 28 (32.2%), and no chromosomal testing in 18 (20.7%). Chromosomal abnormalities were identified in 15 of 41 pregnancies (36.6%) undergoing amniocentesis. Cystic hygroma was independently associated with the selection of invasive diagnostic testing (odds ratio [OR] 3.10, 95% confidence interval [CI] 1.09–9.15), whereas increased nuchal translucency was negatively associated (OR 0.35, 95% CI 0.13–0.90). These findings suggest that the type of first‐trimester ultrasound abnormality is associated with prenatal test selection. Our results highlight the importance of individualized genetic counseling when discussing prenatal testing options and residual uncertainty following abnormal ultrasound findings.