Global research trends in fetal venous Doppler and umbilical vein blood flow: a bibliometric and visualization analysis

OBJECTIVES: Umbilical venous Doppler and umbilical vein blood flow assessment complement arterial Doppler indices by reflecting placental-fetal hemodynamics, venous return, and fetal cardiovascular adaptation. Despite decades of research on fetal venous Doppler, its scientific evolution and the position of umbilical vein blood flow within the field remain insufficiently mapped. This study evaluated global research trends in fetal venous Doppler, emphasizing umbilical venous Doppler and umbilical vein blood flow. METHODS: A bibliometric and visualization analysis was conducted using the Web of Science Core Collection. English-language articles and reviews published between 1980 and 2025 were included. Data were analyzed using bibliometrix and Biblioshiny. Publication trends, citation patterns, leading contributors, collaboration networks, Bradford's Law, keyword co-occurrence, thematic structure, and temporal topic changes were examined. RESULTS: The final dataset included 787 documents from 230 sources, involving 2,692 authors and 12,887 cited references. Scientific output increased steadily, with an annual growth rate of 7.93 %. Ultrasound in Obstetrics & Gynecology was the leading journal, while the United States was the most productive country. Keyword, thematic, and trend analyses identified ductus venosus, umbilical vein, Doppler ultrasound, fetal growth restriction, placental function, perinatal outcome, and fetal hemodynamic adaptation as central themes, with recent trends indicating growing interest in quantitative umbilical vein flow assessment. CONCLUSIONS: Fetal venous Doppler research has expanded steadily over four decades. The increasing focus on umbilical vein blood flow highlights the need for standardized measurement techniques, gestational age-specific reference ranges, reproducibility, and outcome-based validation to clarify its independent clinical value in high-risk pregnancies.