The pregnancy vaginal microbiota in a low-risk Chinese population and its relationship with sialidase activity

The vaginal microbiota during pregnancy influences host responses and preterm birth risk. Majority of preterm births occur in Asia, however, the vaginal microbiota of women outside of Europe and North America is not well established. Here, we characterised the mid-trimester vaginal microbiota of 2796 Chinese women with low-risk pregnancies and in a sub-cohort (n=823), assessed the relationship between the vaginal microbiota, sialidase activity and leukocyte infiltration on pregnancy and neonatal outcomes including preterm birth and neonatal infection. Chinese women vaginal microbiota was mostly dominated by L. crispatus or L. iners. Women with high vaginal sialidase activity had higher bacterial alpha diversity and were associated with BV-type genera including Gardnerella, Atopobium and Prevotella, but not increased risk of preterm birth. Leukocyte infiltration was mainly associated with L. iners dominance. Inclusion of Asian women into future longitudinal studies investigating interactions between the vaginal microbiota, host responses and pregnancy outcomes is warranted.