11 papers reviewed
Vaginal & Endometrial Microbiome
2026 · systematic review / meta-analysis · 1 of 11
The Role of Endometrial Microbiota in the Pathogenesis of Chronic Endometritis: A Systematic Review and Meta-Analysis
— · Biomedicines
Across 22 studies and 4,022 women, chronic endometritis was associated with reduced Lactobacillus-dominated microbiota and enrichment of Enterobacteriaceae, Ureaplasma, Proteobacteria and Chloroflexaceae. Establishes CE as a dysbiosis rather than a simple infection.
Read the paper ↗2024 · review · 2 of 11
Chronic endometritis and the endometrial microbiota: implications for reproductive success in patients with recurrent implantation failure
— · Annals of Clinical Microbiology and Antimicrobials
Chronic endometritis is linked to recurrent implantation failure, recurrent pregnancy loss and unexplained infertility. Dysbiosis drives local inflammation and pro-inflammatory cytokines that compromise endometrial receptivity — a mechanistic bridge between infection and implantation.
Read the paper ↗2021 · systematic review / meta-analysis · 3 of 11
The Association between Vaginal Dysbiosis and Reproductive Outcomes in Sub-Fertile Women Undergoing IVF Treatment: A Systematic PRISMA Review and Meta-Analysis
— · Journal of Clinical Medicine / PMC
Meta-analysis of 17 studies: vaginal dysbiosis is associated with poorer IVF outcomes, and Lactobacillus crispatus-dominant microbiomes are linked to higher implantation and live birth rates. L. crispatus specifically — not Lactobacillus generally — appears protective.
Read the paper ↗2020 · RCT (phase 2b) · 4 of 11
Randomized Trial of Lactin-V to Prevent Recurrence of Bacterial Vaginosis
Cohen CR et al. · New England Journal of Medicine
Live biotherapeutic Lactobacillus crispatus CTV-05 applied vaginally after metronidazole significantly reduced 12-week BV recurrence versus placebo. Colonization was detected in 79-84% of participants at weeks 4-12 and 48% at week 24, versus 2-6% on placebo — demonstrating that the right strain, delivered vaginally, can actually establish.
Read the paper ↗2023 · RCT · 5 of 11
A Healthy Vaginal Microbiota Remains Stable during Oral Probiotic Supplementation: A Randomized Controlled Trial
— · Microorganisms / PMC
Important negative finding: oral Lactobacillus acidophilus La-14 and L. rhamnosus HN001 did not colonize the vagina above detection limits in 50 women. Challenges the common assumption that oral probiotics reach the vaginal tract.
Read the paper ↗2022 · RCT (double-blind) · 6 of 11
Probiotic treatment with specific lactobacilli does not improve an unfavorable vaginal microbiota prior to fertility treatment — a randomized, double-blinded, placebo-controlled trial
— · Frontiers in Cellular and Infection Microbiology / PMC
In 74 women before fertility treatment, vaginal L. gasseri and L. rhamnosus capsules improved microbiota in 34.2% — with no significant difference from placebo. Strain and context matter: not all vaginal probiotics work.
Read the paper ↗2023 · RCT · 7 of 11
Pregnancy outcomes after vaginal probiotic supplementation before frozen embryo transfer: a randomized controlled study
— · Scientific Reports
In 340 infertile women, vaginal Lactobacillus before embryo transfer produced comparable biochemical and clinical pregnancy rates but significantly lower miscarriage (9.5% vs 19.1%), suggesting benefit for maintaining rather than achieving pregnancy.
Read the paper ↗2025 · randomized double-blind placebo-controlled multicentre trial · 8 of 11
Efficacy of clindamycin and LACTIN-V for in vitro fertilization patients with vaginal dysbiosis: a randomised double-blind, placebo-controlled multicentre trial
Haahr T et al. · Nature Communications
In 338 IVF patients with vaginal dysbiosis, clindamycin followed by LACTIN-V did not produce a meaningful improvement in clinical pregnancy compared with control. This high-quality negative trial argues against treating vaginal microbiome products as proven implantation therapy.
Read the paper ↗2024 · randomized parallel-group clinical trial · 9 of 11
Intravaginal probiotics before embryo transfer do not improve pregnancy rates in recurrent implantation failure cases: An RCT
Jafarabadi MN et al. · International Journal of Reproductive BioMedicine
Among 163 analyzed patients with unexplained recurrent implantation failure, intravaginal probiotics before frozen embryo transfer did not significantly improve chemical or clinical pregnancy rates.
Read the paper ↗2024 · observational IVF cohort · 10 of 11
Vaginal microbiota are associated with in vitro fertilization during female infertility
Various · iMeta
A large IVF cohort (n=1,411) found associations between vaginal microbial profiles and IVF outcomes. The study is associative rather than causal and does not establish that probiotic manipulation improves pregnancy.
Read the paper ↗2025 · prospective observational cohort · 11 of 11
Vaginal Microbiome Dominated by Lactobacillus Positively Impacts Clinical Pregnancy in Patients With Frozen Embryo Transfers
Various · Reproductive Sciences
In an 87-patient frozen-embryo-transfer cohort, Lactobacillus-dominant profiles were associated with higher clinical pregnancy. The small observational design cannot separate correlation from a treatment effect.
Read the paper ↗A paper's presence documents the evidence reviewed; it does not mean Filia endorses every intervention or conclusion.