Bibliometric analysis of Hofbauer cell research over the past two decades: Trends and perspectives.

Hofbauer cells (HBC) are fetal-derived placental macrophages crucial for immune regulation, vascular development, and host-pathogen interactions at the maternal-fetal interface. Their growing biological significance and the interdisciplinary, rapidly expanding nature of HBC research make it challenging to comprehensively assess its evolution and emerging priorities. We conducted a comprehensive bibliometric analysis of global HBC research published between 2005 and 2025. Literature was retrieved from the PubMed and Web of Science databases. Using GraphPad Prism and VOSviewer, we analyzed publication trends, geographical distribution, journal impact, author productivity, institutional contributions, and keyword co-occurrence networks. A total of 219 eligible publications were included. Research output increased sharply after 2020, coinciding with growing interest in fetal immunity and viral transmission. The United States led in publication volume, followed by China, the United Kingdom, and Germany. Placenta, Frontiers in Immunology, and American Journal of Reproductive Immunology are the most prolific journals. Yale University emerged as the most influential institution, with its scholars forming a high-impact academic cluster. Keyword clustering revealed four major themes: placental immune regulation, viral transmission, vascular development, and inflammation-related pregnancy disorders. Recent research trends show a shift toward omics technologies and single-cell methodologies. HBC research is undergoing a transformation from descriptive studies to mechanistic and translational investigations. This bibliometric synthesis provides a panoramic overview of the field, identifies key contributors and thematic hotspots, and offers strategic guidance for future research in maternal-fetal immunology.