Over 250 species of bacteria have been detected in the vagina using genomic sequencing. Lactobacillus iners and L crispatus dominate in most women who have a clinically healthy status. Unfortunately, the abundance profiles can change dramatically with significant increases in pathogens associated with bacterial vaginosis (BV) and aerobic vaginitis (AV). The BV microbiota have at least 4 different abundance profiles, indicating this is a complex condition, yet one that is treated with essentially 2 antimicrobial agents which were never designed for eradicting these organisms in dense biofilms. Future studies will uncover which abundance profiles are particularly associated with a risk of preterm labor, and hopefully identify the mechanisms involved in the switch from healthy to a BV or AV state. The use of probiotic lactobacilli vaginally and orally has shown great promise in helping to restore and maintain a healthy vagina, and studies have shown that certain strains have the capacity to interfere with the inflammatory pathway leading to preterm delivery. There is enormous need for new diagnostic and therapeutic modalities, especially to save the lives of millions of babies in resource-disadvantaged countries.