目的·分析母亲孕晚期肠道菌群、阴道菌群、新生儿胎粪及胎皮脂菌群的多样性及菌群构成，比较其异同及相关性。方法·前瞻性研究。招募2018年8月—11月于上海交通大学医学院附属新华医院分娩的11对母婴，采集母亲孕晚期粪便样本、阴道拭子及新生儿胎粪；招募2018年12月于上海交通大学医学院附属国际和平妇幼保健院分娩的14名新生儿，采集额部、腋窝、腹股沟部位的胎皮脂及胎粪样本。所有孕妇均为阴道自然分娩。采用16S rRNA基因V3~V4区测序进行微生物检测，分析11对母婴中母亲的肠道菌群、阴道菌群和新生儿的胎粪菌群，以及14名新生儿的胎皮脂菌群和胎粪菌群的多样性、菌群构成，分析异同及相关性。结果·母亲肠道菌群的操作分类单元（operational taxonomic unit，OTU）数、Ace指数、Chao1指数、Shannon指数均高于阴道菌群和新生儿胎粪菌群；新生儿3个部位胎皮脂菌群的Ace指数和Chao1指数均显著高于胎粪菌群（均P<0.01）。母亲肠道菌群、阴道菌群和新生儿胎粪菌群β多样性存在差异（P<0.01）；新生儿额部、腋窝和腹股沟3个部位胎皮脂菌群的β多样性相似，但与胎粪菌群存在差异（P<0.01）。在门水平上，母亲肠道菌群优势菌主要为厚壁菌门（Firmicutes，52.76%）和拟杆菌门（Bacteroidetes，41.67%），阴道菌群优势菌为厚壁菌门（74.36%）和放线菌门（Actinobacteria，21.25%），胎皮脂菌群的优势菌为厚壁菌门（84.22%）和变形菌门（Proteobacteria，8.80%），新生儿胎粪菌群在2个批次样本中优势菌均为变形菌门（分别占81.11%和88.72%）。在属水平上，母亲肠道菌群的优势菌为拟杆菌属（Bacteroides，35.42%）和栖粪杆菌属（Faecalibacterium，10.12%），阴道菌群的优势菌为乳杆菌属（Lactobacillus，69.10%）和双歧杆菌属（Bifidobacterium，11.30%），胎皮脂菌群的优势菌为乳杆菌属（79.81%）和假单胞菌属（Pseudomonas，3.23%），胎粪菌群的优势菌在2个批次样本中均为埃希菌属（Escherichia，分别占55.21%和31.18%）。结论·母亲孕晚期肠道菌群的α多样性高于阴道菌群和新生儿胎粪菌群，新生儿胎皮脂菌群α多样性高于胎粪菌群。厚壁菌门在母亲孕晚期肠道菌群、阴道菌群及新生儿胎皮脂菌群中均为优势菌，乳杆菌属在母亲阴道菌群及新生儿胎皮脂菌群中均为优势菌，胎粪菌群以变形菌门和埃希菌属较多。新生儿不同身体部位的胎皮脂菌群结构相似，但与胎粪菌群存在差异。

Objective ·To analyze the diversity and composition of the maternal gut microbiota and vaginal microbiota in late pregnancy, neonatal meconium microbiota and vernix caseosa microbiota, and analyze the similarities, differences and correlations. Methods ·This is a prospective study. Maternal stool samples and vaginal swabs in late-pregnancy, and neonatal meconium samples were collected from 11 mother-infant pairs at Xinhua Hospital, Shanghai Jiao Tong University School of Medicine from August to November 2018; the vernix caseosa from three sites (forehead, axilla, and inguinal crease) and meconium samples were collected from 14 healthy newborns at International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine in December 2018. All births were vaginal deliveries. The 16S rRNA gene V3?V4 region sequencing was used. The diversity, composition and similarities/differences of the maternal gut microbiota, the vaginal microbiota, and the neonatal meconium microbiota from the 11 mother-infant pairs, as well as the neonatal vernix caseosa microbiota and the meconium microbiota from the 14 newborns were analyzed. Results ·The number of operational taxonomic units (OTUs), ACE index, Chao1 index, and Shannon index of maternal gut microbiota were all higher than those of vaginal microbiota; the ACE indices and the Chao1 indices of the vernix caseosa microbiota at three sites were all higher than those of meconium microbiota (P<0.01). The β diversity varied among the maternal gut microbiota, vaginal microbiota, and neonatal meconium microbiota (P<0.01). The β diversity of neonatal vernix caseosa microbiota from three sites (forehead, axilla, and inguinal crease) was similar, but different from meconium microbiota (P<0.01). At the phylum level, the dominant bacteria were Firmicutes (52.76%) and Bacteroidetes (41.67%) in the maternal gut microbiota, Firmicutes (74.36%) and Actinobacteria (21.25%) in the maternal vaginal microbiota, and Firmicutes (84.22%) and Proteobacteria (8.80%) in the neonatal vernix caseosa microbiota. The dominant bacterium in the neonatal meconium was Proteobacteria in the two batches of samples (81.11% and 88.72%, respectively). At the genus level, the dominant bacteria were Bacteroides (35.42%) and Faecalibacterium (10.12%) in the maternal gut microbiota, Lactobacillus (69.10%) and Bifidobacterium (11.30%) in the vaginal microbiota, and Lactobacillus (79.81%) and Pseudomonas (3.23%) in the vernix caseosa microbiota. The dominant bacterium in the neonatal meconium was Escherichia in the two batches of samples (55.21% and 31.18%, respectively). Conclusion ·The α diversity of maternal gut microbiota is higher than that of vaginal microbiota and neonatal meconium microbiota, and it is higher in neonatal vernix caseosa than that in meconium microbiota. The Firmicutes is the predominant phylum in the maternal late-pregnancy gut microbiota, vaginal microbiota, and neonatal vernix microbiota. Lactobacillus is the predominant genus in both maternal vaginal and neonatal vernix caseosa microbiota. Proteobacteria in phylum and Escherichia in genus are predominant in meconium microbiota. The microbiota composition is similar in vernix caseosa at different body sites, but there are differences between the vernix caseosa microbiota and meconium microbiota.