O-281 Characterization of Vaginal microbiota and reproductive outcomes associated with assisted reproductive technologies through next-generation sequencing, from Indian population
Authors: Vajpeyee D  M , Tiwari S , Yadav L  B 
Published: July 2024

Abstract

Study question
Is there any association between the composition of the vaginal microbiota and the reproductive outcomes in infertile women’s undergoing for assisted reproductive treatments (ART)?

Summary answer
Higher microbial abundance in non-pregnant patients compared to pregnant patients. These pathogens could be used as a possible marker for a higher IVF failure rate.

What is known already
Various next- generation sequencing methods have been used to study bacterial populations in infertile Women. Vaginal microbiota could have an influence on success rates of fertility treatments. The bacterial microbiota varies by the population. There is no direct evidence on this subject to guide clinical decision making or its influence on the hierarchy of fertility treatments. While the presence of pathogenic bacteria non-Lactobacilli dominated microbiota is associated with poor reproductive outcomes in assisted reproductive treatments (ART). Additional studies, particularly those using metagenomics approaches, may be useful.

Study design, size, duration
A total of 240 infertile women’s were included in the study. The study population consists of patients attending to the ART unit of a tertiary medical center Udaipur, India, between November 2021 to October 2023.
Depending on the biochemical pregnancy results, they were divided into two groups. Group 1 (n = 128) was pregnancy (P), and Group 2 (n = 112) non- pregnancy (NP) group, Patients were aged between (20-45 years). The ethical approval was obtained from the institute.

Participants/materials, setting, methods
DNA was extracted from vaginal swab samples collected at the time of oocyte pick up using the commercially available ( DNeasy Power Soil kit). The Vaginal microbiota of samples were analyzed using 16S ribosomal RNA gene amplification (MinION) Oxford Nanopore Ltd. Bioinformatics analysis was performed using QIIME2 and Microbiome Analyst packages. Alpha, beta diversity and taxonomic characterization were compared for microbial composition. The findings of the principle coordinate analysis were shown using R version 4.0.

Main results and the role of chance
Our results show that higher Shannon and Simpson index were obtained in the non- pregnancy (NP) group compared to the pregnancy (P) group.
In addition, the partial least squares discriminant analysis (PLS-DA) revealed a difference in microbial composition between pregnancies (P) and non- pregnancy (NP) groups, as well as a higher microbial abundance in non-pregnant patients compared to pregnant patients.
At the phylum level Firmicutes, Actinobacteria, Proteobacteria, Fusobacteria, and Bacteroidetes are the most common predominant in the pregnancy (P) group (80.77, 9.52, 9.18, 0.04, and 0.40%, respectively) and the non- pregnancy (NP) group (72, 61, 12.41, 8.01, and 3.75%).
A higher abundance of Firmicutes (80.77 vs. 72.61%) and Proteobacteria (9.18 vs. 8.01%), and a lower abundance of Actinobacteria (9.52 vs. 12.41%, p = 0.03), Fusobacteria (0.04 vs. 8.01%, p = 0.02), and Bacteroidetes (0.40 vs. 3.75%, p = 0.03) were observed in pregnancy (P) group.
At the genus level, pregnancy group (P) increased the abundance of probiotics lactic acid bacteria (74.61 vs 63.09%) and decreased the abundance of the pathogen Gardnerella (6.03 vs 7.24%, p = 0.03), Atopobium (0.84 vs 4.14%, p = 0.02), Sneathia (0.03 vs. 3.75%, p = 0.02), and Prevotella (0.38 vs. 3, 02%, p = 0.04).

Limitations, reasons for caution
The limited sample size is the primary constraint of this study. Larger studies with a larger sample size are needed to confirm the distinct microbiome patterns identified in female reproductive tracts samples in connection to infertility and live birth rate (LBR) outcomes.

Wider implications of the findings
Vaginal microbiota composition associated to different clinical outcomes in patients undergoing ART might have profound implications. This may lead to failed fertility treatments and reduced live birth rate (LBR). More studies are needed to clarify the relative effectiveness of treatments for infertility.

Trial registration number
NA