Precision Microbial Therapeutics for Infertility: Next-Generation Probiotics, Engineered Biologics and Translational...

Area of Science:

• Reproductive Medicine
• Microbiome Research
• Infectious Diseases

Background:

• Infertility affects approximately 1 in 6 reproductive-age individuals, with heterogeneous causes and incomplete diagnostics.
• The female reproductive tract harbors a unique, low-biomass microbial ecosystem.
• Microbial dysbiosis, characterized by reduced Lactobacillus and increased pathobionts, is associated with implantation failure and recurrent pregnancy loss.

Purpose of the Study:

• To review the contrasting roles of receptive (Lactobacillus-dominant) and dysbiotic reproductive tract microbial states in fertility.
• To summarize mechanisms by which the microbiota influences fertility, including microbial metabolites and inflammation.
• To outline a roadmap for developing and implementing microbiome-directed therapies for infertility.

Main Methods:

• Narrative review of existing literature on the reproductive microbiome and fertility.
• Contrast of Lactobacillus-dominant vs. dysbiotic states.
• Summary of mechanisms linking microbiota to fertility outcomes.

Main Results:

• Observational data consistently link Lactobacillus dominance to improved fertility outcomes, though evidence quality is low-to-moderate.
• Dysbiosis can impair implantation through inflammation, while beneficial metabolites support barrier function and immune tolerance.
• Numerous precision microbial therapeutics are under development, including probiotics, synthetic consortia, and microbiota transplantation.

Conclusions:

• The reproductive microbiome represents a promising frontier for infertility treatment, but requires further validation.
• Standardized diagnostics, mechanistic studies, and rigorous clinical trials are needed to translate microbiome research into clinical practice.
• A diagnostic-driven approach matching microbiome endotypes to specific interventions is proposed.