Plain language summary
Efforts to improve pregnancy rates remain largely focused on enhancing the quality of the transferred embryo. However, there is increasing awareness of the potential role of the intra-uterine environment as a determinant for success. The aim of this study was to determine if lactobacilli-loaded vaginal capsules are superior to placebo in improving a vaginal microbiota reported as unfavourable to implantation in women scheduled for fertility treatment. This study is a single-centre, two-arm, double-blinded, randomised controlled study. The study enrolled women aged 18–40 years who were referred to the Fertility Clinic and whose vaginal microbiota prior to fertility treatment had been diagnosed as an unfavourable. Participants (n=77) were randomised in a 1:1 ratio to either lactobacilli-loaded vaginal capsules or placebo. Results did not show any significant effect of treatment with lactobacilli-loaded vaginal capsules on the unfavourable vaginal microbiota profile among women referred to fertility treatment. However, the study showed the highly dynamic nature of the vaginal microbiota, with a spontaneous improvement rate of 34.2% (of the patients) one to three months after the baseline sample. Authors conclude that probiotics use for the improvement of vaginal microbiota should be tempered with some caution. More studies of both the vaginal and endometrial microbiota are required to confirm the efficacy of specific vaginal probiotics before they can be considered as a therapeutic solution.
Abstract
OBJECTIVE To investigate whether treatment with proprietary lactobacilli-loaded vaginal capsules improves an unfavorable vaginal microbiome diagnosed using a commercially available test and algorithm. DESIGN A randomized, double-blinded, placebo-controlled study was conducted in 74 women prior to undergoing fertility treatment at a single university fertility clinic between April 2019 and February 2021. The women were randomly assigned in a 1:1 ratio to receive one vaginal capsule per day for 10 days containing either a culture of more than 108 CFU of Lactobacillus gasseri and more than 108 CFU Lactobacillus rhamnosus (lactobacilli group) or no active ingredient (placebo group). Vaginal swabs for microbiota analysis were taken at enrollment, after treatment and in the cycle following treatment. PARTICIPANTS AND METHODS Women aged 18-40 years who prior to fertility treatment were diagnosed with an unfavorable vaginal microbiota, characterized by either a low relative load of Lactobacillus or a high proportion of disrupting bacteria using the criteria of the IS-pro™ diagnostic system (ARTPred, Amsterdam, the Netherlands), were enrolled in the study. The primary outcome measure was the proportion of women with improvement of the vaginal microbiota after intervention. RESULTS The vaginal microbiota improved after intervention in 34.2% of all participants (lactobacilli group 28.9%, placebo group 40.0%), with no significant difference in the improvement rate between the lactobacilli and placebo groups, RR = 0.72 (95% CI 0.38-1.38). CONCLUSION This study indicates that administering vaginal probiotics may not be an effective means of modulating the vaginal microbiome for clinical purposes in an infertile population. However, a spontaneous improvement rate of 34.2% over a period of one to three months, confirming the dynamic nature of the vaginal microbiota, indicates that a strategy of postponing further IVF treatment to await microbiota improvement may be relevant in some patients, but further research is needed. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, identifier NCT03843112.
Methodological quality
Jadad score
:
5
Allocation concealment
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Yes
