Vaginal Lactobacillus crispatus group early in pregnancy and preferable pregnancy course: Japanese maternal-neonatal microbiome cohort

The maternal microbiome during pregnancy and the peripartum period plays a vital role in maternal health and the development of the neonatal gut microbiome, with long-term implications for offspring health. However, a clear definition of a "healthy microbiome" during these critical periods remains elusive. This comprehensive longitudinal study examined maternal and neonatal microbiomes in a Japanese cohort throughout pregnancy and postpartum. The maternal vaginal microbiome remained stable during pregnancy but underwent significant changes postpartum. Among Lactobacillus species, the Lactobacillus crispatus group was predominant, and its dominance early in pregnancy was associated with favorable gestation outcomes. The maternal gut microbiome showed minimal compositional changes during pregnancy but was found to correlate with the vaginal microbiome. In contrast, the neonatal gut microbiome exhibited dramatic shifts early in life, with delivery mode significantly influencing its bacterial composition. Over time, bacteria derived from the maternal gut microbiome became dominant, surpassing those from other maternal sites. This study highlights the characteristics of a healthy microbiome in Japanese mothers and their children during pregnancy and postpartum. Identifying commonalities across diverse populations could enhance our understanding of key microbes in human health and contribute to the development of microbiome-based interventions in the future.