Vaginal Lactobacillus crispatus in early pregnancy associates with favorable gestational outcomes in a Japanese maternal-neonatal microbiome cohortOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study tracked how maternal and neonatal microbiomes change through pregnancy and early life in a Japanese population. Researchers used 16S rRNA amplicon sequencing of the V4 region. They sampled maternal vaginal and gut sites at weeks 12, 20, 30, and 36, at delivery, and one month postpartum. Neonatal rectal samples were collected on days 0, 1, and 4 and at one month. They classified Lactobacillus to the subgenus level and linked microbiome features to gestational outcomes and delivery mode. This is described as the first such longitudinal analysis in Japan.
Who was studied?
Participants were 42 mothers and their 45 offspring, enrolled at Kyorin University Hospital in western Tokyo, Japan. Women were recruited between October 2021 and January 2022, with follow-up to September 2022. Maternal vaginal, gut, and skin samples were collected across pregnancy, delivery, and postpartum. At cesarean delivery, skin swabs replaced gut swabs. In total, 239 maternal vaginal samples, 220 maternal gut samples, and 143 neonatal rectal samples were analyzed. Detailed clinical data accompanied each mother and infant.
What were the most important findings?
The vaginal microbiome stayed relatively stable through pregnancy but changed significantly postpartum. During pregnancy Lactobacillus was the dominant genus at 77.78 percent, falling to 9.24 percent postpartum, with the Lactobacillus crispatus group predominant. Mothers with Lactobacillus-dominant vaginas at week 12 were far more likely to continue pregnancy beyond 38 weeks, at 89.66 percent versus 50.00 percent for others. Late-pregnancy abundance showed no such association. Neonatal gut composition shifted with delivery mode. Over the first month, shared bacteria increasingly resembled the maternal gut rather than the vaginal microbiome.
What are the greatest implications of this study?
The results suggest that vaginal Lactobacillus, especially the crispatus group, early in pregnancy plays a role in supporting a favorable gestational course in this Japanese cohort. This adds population-specific evidence toward defining a healthy perinatal microbiome. The associations are observational, so causation cannot be inferred. Higher pre-pregnancy body mass index also linked to Lactobacillus dominance, complicating interpretation. The single-center design, limited sample size, one-month follow-up, and use of genus-level 16S sequencing constrain the findings. The authors call for larger, longer, multi-population studies.