The Disordered Vaginal Microbiota Is a Potential Indicator for a Higher Failure of in vitro Fertilization

Abstract

Infertility is one of the most common reproductive system diseases, and no effective method is available for its treatment. Although in vitro fertilization (IVF) has been widely used to enhance the clinical pregnancy outcome of infertility, the unsatisfied pregnancy rate with unknown reasons is obtained. To identify the possible cause of IVF failure, 555 patients were enrolled in the present study to determine their relevant clinical characteristics and vaginal microbiota. Our results indicated that the age and endometrium thickness significantly affected the pregnancy success rate of pregnant patients (P group) and non-pregnant patients (NP group) receiving IVF, and high values of luteinizing hormone, estrogen and progesterone were observed from P group. Furthermore, the Partial Least Squares Discriminant Analysis (PLS-DA) indicated a different microbial composition in P group and NP group, and a higher microbial abundance had been identified in non-pregnant patients compared with pregnant patients. At phylum level, a higher abundance of Firmicutes and Proteobacteria, and a lower abundance of Actinobacteria, Fusobacteria, and Bacteroidetes were obtained in pregnant patients compared with non-pregnant patients. At genus level, a lower abundance of the probiotic Lactobacillus, and higher abundance of pathogens Gardnerella and Prevotella were identified from non-pregnant patients. Therefore, the disordered microbiota, characterizing by the reduction of probiotics and overgrowth of pathogens in non-pregnant patients, may be used as a potential indicator for a higher IVF failure rate.

The Association between Vaginal Dysbiosis and Reproductive Outcomes in Sub-Fertile Women Undergoing IVF-Treatment: A Systematic PRISMA Review and Meta-Analysis

“…Hence, a total of 11 citations were assessed for eligibility by examination of the full text. Two studies were removed due to study design [ 32 , 33 ] and three were removed as it was not possible to extract pregnancy outcome data for meta-analysis [ 34 , 35 , 36 ]. Two studies were based on the same study population [ 5 , 29 ], and only the initial publication was included [ 5 ], but data on LBR was extracted from the later study [ 29 ].…”

“…The authors of Moragianni et al [ 37 ] were contacted to clarify their definition of pregnancy and the authors provided relevant data for study inclusion. Additionally, we contacted authors of three studies [ 34 , 35 , 36 ] but received no response and consequently their data could not be evaluated in the present meta-analysis.…”

The Association Between Vaginal Microbiota Dysbiosis, Bacterial Vaginosis, and Aerobic Vaginitis, and Adverse Pregnancy Outcomes of Women Living in Sub-Saharan Africa: A Systematic Review

“…It has been proposed that the increased risk of adverse reproductive and pregnancy outcomes might be attributable to BV-related bacterial species rather than BV itself. In the context of in vitro fertilization (IVF) studies, patients with high incidence of Gardnerella, Atopobium , and Prevotella failed to become pregnant after embryo transfer or experienced miscarriage ( 49 , 50 ). Indeed, in early pregnancy, the reduction in lactobacilli and the overgrowth of Gardnerella, Atopobium , and Prevotella genera disrupt the microbial homeostasis, hindering embryo implantation ( 49 ).…”

Cervicovaginal microbiota and women’s health outcomes

“…Initially Hyman et al 20 associated diverse vaginal bacteria with poor IVF outcomes and suggested that the composition of the microbiome at the time of embryo transfer may be an important factor in the success of IVF treatment. Since this initial study there have been several others that have associated increased diversity of cervicovaginal microbiota and the presence of specific bacteria, with IVF failure [25][26][27] . However, there is no defined profile of microbiota associated with poor outcomes in IVF treatment, mostly due to the lack of larger studies.…”