The Gestational Vaginal Microbiome and Spontaneous Preterm Birth among Nulliparous African American Women

Introduction Early markers to identify pregnant women at high risk for spontaneous preterm birth (SPTB) have not been established and preventive options are limited. Recent attention has focused on examining the importance of characterizing the vaginal microbiome to predict SPTB. Results We examined the diversity and structure of the vaginal microbiome in nulliparous African American women during early pregnancy and compared 13 women who delivered preterm and 27 women who delivered at term. Samples were taken at one of two points in gestation, before 16 weeks or between 20 and 24 weeks. Among women who delivered preterm, we found lower bacterial diversity with lower abundance of Coriobacteriaceae, Sneathia, Prevotella, and Aerococcus compared with women delivering at term (linear discriminant analysis score > 3.0). The Shannon diversity index was not significantly different between the groups (p-value = 0.239). Phylogenetic diversity and Chao1 suggested a lower diversity in the vaginal microbiota of women who delivered preterm compared with term, but these findings were not significantly different (p = 0.077 and p = 0.066, respectively). Conclusion These data suggest that the vaginal microbiome of women delivering preterm had lower diversity than women delivering after 37 weeks, although these findings need to be explored in a larger sample of nulliparous African American women.