Viromic profiling of amniotic fluid reveals distinct viral communities associated with maternal health status

BACKGROUND: Amniotic fluid is a critical compartment in pregnancy; however, its virome remains poorly characterized, and potential associations with maternal–fetal health are largely unexplored. This study aimed to comprehensively profile the human amniotic fluid virome and explore its association with maternal health status during pregnancy. METHODS: We performed viral metagenomic sequencing of 515 amniotic fluid samples from 515 pregnant women in Changzhou, China, including healthy pregnancies (n = 275) and pregnancies with complications (n = 240). Viral sequences were identified using a bioinformatics pipeline, and phylogenetic analyses were used to assess genetic relationships. RESULTS: We identified diverse viral sequences, including members of viral families such as Anelloviridae and Paramyxoviridae. BLAST-based nucleotide comparisons showed high nucleotide identity to previously reported viruses, indicating that many detected sequences are closely related to known viruses. Phylogenetic analyses further supported their placement within established viral taxa. Community-level analyses indicated differences in virome composition profiles between the healthy control and disease groups. CONCLUSIONS: Our findings describe a previously undercharacterized virome in human amniotic fluid. This study establishes a basis for future investigations into the origins and potential associations of these viral signatures with pregnancy health, highlighting the importance of assessing their clinical relevance for both maternal and neonatal outcomes. Because metagenomic sequencing detects viral nucleic acids, these findings do not establish viral infectivity or causality.