Title Vaginal Microbiota Changes of Gestational Diabetes Mellitus Pregnant Women at Different Gestational Weeks and the Impact on Pregnancy Outcome: a Prospective Cohort Study

Background Gestational diabetes mellitus (GDM) is a common complication of pregnancy, and previous studies have shown that pregnant women with GDM have a higher risk of developing infectious diseases of the reproductive tract than healthy pregnant women, but relevant cohort studies are rare. Objective To investigate the variation characteristics of vaginal microbiota in pregnant women with GDM at different gestational weeks, to compare the differences of vaginal microbiota between GDM and non-GDM women, and to observe the effects of vaginal microbiota changes on pregnancy outcomes. Methods In this study, we used a consecutive sampling method to recruit pregnant women who established their records and regulated health care at Daxing Teaching Hospital of Capital Medical University from March 2022 to March 2023. They underwent 75 g oral glucose tolerance test (OGTT) at 24-28 weeks of gestation to diagnose GDM. The GDM group was matched 1∶1 with the non-GDM group using propensity score matching method (PSM). Samp