The reproductive tract microbiota in IVF
File(s)
Author(s)
Mowla, Shahriar
Type
Thesis
Abstract
Reproductive tract microbiota play an important role in health and disease. In pregnancy, loss of commensal vaginal bacteria and increased bacterial diversity associate with poor reproductive outcomes. Several studies have implicated the microbiota in success of fertility treatments with inconsistent results. The impact of hormonal manipulation during in vitro fertilisation (IVF) on the vaginal microbiota and host immune response is poorly defined. To address this, women undergoing fresh/frozen IVF cycles were recruited. Interactions between sex hormones, immune analytes and bacterial composition in fresh IVF cycles were examined and several relationships were observed. E2 had an anti-inflammatory effect during IVF cycles with inverse relationships with immune mediators. IL-1β and IL-8 were found to be significantly higher in cervico-vaginal samples of patients with successful treatment outcomes during embryo transfer. Furthermore, enrichment for L. crispatus was associated with unsuccessful frozen IVF cycles. Regardless, the vaginal microbiota was not a strong predictor of IVF outcome in the cohorts investigated. However, a pilot study examining the cervicovaginal metabolome in these women highlighted the potential of metabolic profiling to both discriminate vaginal microbiota composition and predict success of IVF treatment outcome.
The investigations described in this thesis provide a new insight into the vaginal and seminal microbiota and their role in shaping fertility outcomes. Modulation of sex hormones during IVF treatment shapes clinically relevant microbiota-host interactions despite the data indicating that the vaginal microbiota is not a strong predictor of IVF success. However, the assessment of the vaginal metabolome by DESI-MS provides potential to predict bacterial composition and treatment outcome during IVF. Finally, results confirming that semen harbours a microbiome that modulates parameters of sperm quality and function highlights the importance of examining male and female partners in futures studies investigating the role of the microbiome in reproductive outcomes.
The investigations described in this thesis provide a new insight into the vaginal and seminal microbiota and their role in shaping fertility outcomes. Modulation of sex hormones during IVF treatment shapes clinically relevant microbiota-host interactions despite the data indicating that the vaginal microbiota is not a strong predictor of IVF success. However, the assessment of the vaginal metabolome by DESI-MS provides potential to predict bacterial composition and treatment outcome during IVF. Finally, results confirming that semen harbours a microbiome that modulates parameters of sperm quality and function highlights the importance of examining male and female partners in futures studies investigating the role of the microbiome in reproductive outcomes.
Version
Open Access
Date Issued
2023-05-25
Date Awarded
2024-03-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
MacIntyre, David
Bennett, Phillip
Publisher Department
Department of Metabolism, Digestion and Reproduction
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)