[Spontaneous preterm birth and the maternal microbiome].

Preterm birth is the leading cause of perinatal mortality and morbidity. Despite the efforts spent over the past 40 years to solve the physiopathological processes involved in the triggering of prematurity, efficient therapeutics are still lacking. Recently, growing body of evidence suggests that the maternal microbiome is a major player for a normal pregnancy and that dysbiosis is associated with preterm birth. The vaginal microbiome and its commensal Lactobacillus species may protect the uterus of ascending dissemination of pathogens. The uterus can also be contaminated with oral bacteria by the blood stream. Thus, the maternal microbiome can play both a protective role or a causal role in the triggering of preterm birth.