Roberto Costillas Perez: Vaginal Microbiota’s Role in Assisted Reproduction Outcomes
Roberto Costillas Perez, Founder and CEO at Fertypharm, shared a post on LinkedIn:
“Vaginal Microbiota and Outcomes in Assisted Reproduction (Summary)
A Lactobacillus-dominated vaginal microbiota, especially L. crispatus, favors an acidic and protective environment, associated with better outcomes in assisted reproduction.
Vaginal dysbiosis (elevated pH, predominance of anaerobes like Gardnerella, Prevotella or Atopobium) correlates with lower implantation rates, higher miscarriage and worse overall prognosis.
Impact on Reproductive Outcomes
Lactobacillus-dominated Microbiota
- Implantation Rate: 40–60%
- Clinical Pregnancy: 45–65%
- Spontaneous Miscarriage: 10–20%
- Live Birth: 35–55% per transfer
Vaginal Dysbiosis
- Implantation: reduction of ~30–40%
- Clinical Pregnancy: 20–35%
- Miscarriage: 20–30%
- Live Birth: 15–30% per transfer
Clinical Management
1. Accessible Basic Screening
- A simple vaginal pH strip is a quick and useful method:
- pH > 4.5 → suggests dysbiosis or bacterial vaginosis.
- It allows identifying patients who could benefit from a more detailed assessment in assisted reproduction contexts.
2. When to Study Vaginal Microbiota
Indicated in:
- Repeated implantation failures
- Recurrent miscarriages
- Recurrent vaginosis or suspicion of clinically relevant dysbiosis
- Not recommended as routine screening for all patients.
3. Recommended Interventions
- Oral probiotics with lactobacilli
- They can be a good strategy to promote or restore a eubiotic environment before and during assisted reproduction cycles.
- Evidence particularly supports strains like L. rhamnosus and L. Plantarum and L. Crispatus.
- Antibiotic treatment only if documented dysbiosis exists (PCR, NGS or clinical with elevated pH and symptoms), avoiding indiscriminate empirical use.
- Re-evaluation (pH or specific tests) before embryo transfer in cases of prior dysbiosis.
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