Dangling Choroid Plexus: An Early Sign of Fetal Anomaly

Objectives: This study aimed to examine the association between the dangling choroid plexus sign and fetal structural, chromosomal, and genetic abnormalities, as well as to define the normal range of lateral ventricular width and the ratio of choroid plexus width to lateral ventricular width at 14-17 weeks of gestation. Methods: This retrospective study analyzed ultrasound images from early fetal anatomy scans performed between January 2018 and July 2025 at two tertiary fetal medicine centres. In centre A, 6063 singleton pregnancies underwent routine scans at 11-13 and 14-17 weeks. In centre B, 776 fetuses with suspected abnormalities or increased nuchal translucency at 11-13 weeks were reassessed at 14-17 weeks. Additionally, 400 fetuses without obvious abnormalities at 14-17 weeks were used to determine normal ventricular measurements. Results: In normal fetuses, the mean lateral ventricular width was 6.90 mm (95% CI 6.81-6.99) and the mean choroid plexus-to-ventricle ratio was 0.85 (95% CI 0.84-0.86). A dangling choroid plexus was identified in 38 fetuses (0.16% in routine and 3.6% in high-risk populations). Out of 38 cases of dangling choroid plexus, 37 were associated with additional structural defects, chromosomal abnormalities, or single-gene disorders. Chromosomal abnormalities were found in 11/30 tested cases, most commonly trisomy 21. The most common defects observed on initial or subsequent scans were ventriculomegaly, cardiac defects, and abnormal posterior fossa. Conclusions: A dangling choroid plexus at 14-17 weeks is a sonographic marker associated with major fetal abnormalities and should prompt detailed anatomical assessment and consideration of genetic testing.