Assessment of bacterial diversity associated with assisted reproductive technologies through next-generation sequencing

Abstract

Background To assess bacterial diversity in infertile couples with their biochemical pregnancy outcomes. Using a retrospective case-control study design, participants were recruited for collection of vaginal swab, follicular fluid, endometrial fluid, and semen samples. The microbial composition was analyzed by 16S ribosomal RNA (rRNA) gene amplification with (MinION) Oxford Nanopore Ltd. Results Our findings revealed that age and endometrial thickness had a significant impact on the pregnancy success rate of pregnant (P) and non-pregnant (NP) patients receiving IVF, with high levels of luteinizing hormone, estrogen, and progesterone in the P group. In addition, the partial least squares discriminant analysis (PLS-DA) revealed a difference in microbial composition between the P and NP groups, as well as a higher microbial abundance in non-pregnant patients compared to pregnant patients. After comparison between pregnant patients and non-pregnant patients, pregnant patients had a higher abundance of Firmicutes and Proteobacteria and a lower abundance of Actinobacteria, Fusobacterium, and Bacteroidetes at the phylum level. Non-pregnant patients had a lower abundance of the probiotics lactobacillus and a higher abundance of infections Prevotella and Gardnerella at the genus level. As a result, a disordered microbiota in non-pregnant patients, characterized by a decrease in probiotics and an increase in pathogens, could be used as a possible marker for a higher IVF failure rate. Conclusion Alteration of the microbiota of the reproductive tract or the presence of certain microbes, regardless of the degree of pathogenicity that can affect fertilization, as well as implantation and subsequent embryonic development. This could result in failed fertility treatments and a lower live birth (LBR) rate.

Vaginal dysbiosis – the association with reproductive outcomes in IVF patients: a systematic review and meta-analysis

“…Additionally, we contacted the authors of four studies [40][41][42][43] to provide additional data. From three studies [40][41][42][43], we received no response, and consequently, their data could not be evaluated. The authors of one study [41], provided data, however, the study did not meet the inclusion criteria regardless.…”

“…Seven studies were removed due to study design [29,33–36,38,39] and four were removed as it was not possible to extract pregnancy outcome data for the meta-analysis [30–32,37]. Further searches in additional databases yielded five relevant papers [23 ▪ ,40–43], however, only the study by Väinämö et al [23 ▪ ] met the eligibility criteria and was included. Additionally, we contacted the authors of four studies [40–43] to provide additional data.…”

“…Further searches in additional databases yielded five relevant papers [23 ▪ ,40–43], however, only the study by Väinämö et al [23 ▪ ] met the eligibility criteria and was included. Additionally, we contacted the authors of four studies [40–43] to provide additional data. From three studies [40–43], we received no response, and consequently, their data could not be evaluated.…”

Pregnancy outcomes after vaginal probiotic supplementation before frozen embryo transfer: a randomized controlled study

“…A lactobacilli-predominant vaginal and endometrial environment has been associated with a higher pregnancy rate 24 , 25 and a lower miscarriage rate 13 . We studied the clinical outcomes of intravaginal probiotic supplementation before ET during the frozen-thaw cycle.…”