Vaginal microbiome and preterm birth: Composition, mechanisms and microbiota‑directed therapies (Review).

A small study of nulliparous African-American women noted a nonsignificant trend toward reduced diversity in spontaneous PTB ( 75 ), and another black cohort found that although specific Lactobacillus abundances were not linked to PTB risk, lower overall diversity associated with PTB among African-American women ( 76 ).

also in 5,406 other papers