Genetic and Sonographic Insights into First-Trimester Fetal Cystic Hygroma: A Retrospective 30-Year Analysis Using 3D/4D Ultrasound and Cytogenetic Evaluation in Croatia (1993–2023)

The finding and diagnosis of cystic hygroma in first trimester and early second-trimester pregnancy represent a strong predictor of chromosomal aneuploidy and warrant comprehensive prenatal genetic testing and close follow-up. However, in the absence of genetic abnormalities and additional malformations, spontaneous resolution is common, and neonatal outcomes are generally favorable. Health systems should provide equitable access to genetic testing and fetal imaging to support accurate diagnosis and informed decisions.