The Vaginal Microbiome in U.S. Black Women: A Systematic Review

Background: Advancements in next-generation sequencing have allowed for a more complete understanding of the vaginal microbiome and its role in health and disease. The role of race/ethnicity in the composition of the vaginal microbiome and what is deemed normal/healthy microbiome is conflicting. Thus, the purpose of this review is to synthesize research that investigated the vaginal microbiome in Black women in the United States by using advanced 16S analysis. Methods: Searches of Pubmed, Google Scholar, and relevant journals for publications between January 2008 and July 2018 were conducted. Eligibility criteria were that the study: (1) used a molecular technique for sequencing of the vaginal microbiome, (2) reported the microbiome by race/ethnicity that included Black women, and (3) was conducted in the United States. Results: Our review selected 18 manuscripts that met the inclusion criteria for full review. Three themes emerged: the vaginal microbiome in healthy women versus women with bacterial vaginosis (BV); vaginal microbiome considerations in HIV; and vaginal microbiome considerations in preterm labor/birth. Overall, our review found that a majority of Black women (including HIV-positive women) have a Lactobacillus dominant group. Specifically, Lactobacillus iners was the most frequently reported Lactobacillus species. Non-Lactobacillus dominant groups were also reported to be found in healthy asymptomatic Black women. The vaginal microbiome's influence on preterm labor and/or birth among Black women was inconclusive and warrants further investigation. Conclusions: The role that the microbiome plays in health and disease among Black women warrants further research to better elucidate the definition of a healthy versus pathogenic microbiome. The wide variability in methods for BV diagnostics and defining preterm labor/birth are significant limitations that should be considered when conducting comparative studies.