Is it safe for a woman preparing for an IVF cycle to take the oral probiotic Fertibiome (Ligilactobacillus salivarius), and what dosing schedule should be used?

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Fertibiome (Ligilactobacillus salivarius) for IVF Preparation

Direct Recommendation

Oral Ligilactobacillus salivarius CECT5713 (the strain in Fertibiome) is safe for women preparing for IVF and should be administered at 3 × 10⁹ CFU once daily, starting at least 2-6 months before the planned IVF cycle. 1, 2


Safety Profile

General Safety in Reproductive-Age Women

  • Probiotics containing lactobacilli are generally safe for healthy, immunocompetent women of reproductive age, with the overwhelming evidence suggesting safety in the general population. 3

  • Ligilactobacillus salivarius specifically has demonstrated safety in clinical trials involving couples with unexplained infertility, with no serious adverse events reported during 6-month supplementation periods. 1, 2

  • Minor gastrointestinal side effects (bloating, cramping, abdominal discomfort) may occur but are typically mild and self-limited. 4

Critical Safety Exclusions

Do not use probiotics if the patient has any of the following conditions:

  • Immunocompromised status (HIV, chemotherapy, immunosuppressive medications) due to documented risk of bacteremia and sepsis from probiotic organisms. 4
  • Central venous catheters (increased risk of line-associated infections). 4
  • Cardiac valvular disease (risk of endocarditis from bacteremia). 4
  • Damaged intestinal mucosa or short-gut syndrome (increased bacterial translocation risk). 4
  • Severe acute pancreatitis (associated with increased mortality in this specific population). 4

Dosing Protocol for IVF Preparation

Recommended Regimen

Administer 3 × 10⁹ CFU of Ligilactobacillus salivarius CECT5713 orally once daily, starting 2-6 months before the planned IVF cycle and continuing until pregnancy is confirmed or the IVF cycle is completed. 1, 2

Route of Administration

  • Oral administration is the preferred and evidence-based route for Ligilactobacillus salivarius CECT5713, as this strain has been specifically studied via oral supplementation with demonstrated efficacy in improving pregnancy rates. 1, 2

  • While vaginal probiotics are used for treating bacterial vaginosis, oral administration of L. salivarius CECT5713 has shown superior evidence for fertility outcomes, achieving a 48.1% pregnancy success rate compared to 20.0% in placebo groups. 1

Duration Considerations

  • Minimum treatment duration should be 2 months to allow adequate time for microbiome modulation and immunological profile improvement. 2

  • Optimal duration appears to be 6 months based on studies showing progressive improvement in urogenital microbiome composition and resolution of dysbiosis in 67% of couples by 6 months. 2

  • Continue supplementation through the IVF cycle until pregnancy is confirmed, as the probiotic effects on vaginal and endometrial microbiome require ongoing maintenance. 1


Mechanism and Expected Benefits

Microbiome Modulation

  • L. salivarius CECT5713 improves vaginal microbiome composition by increasing Lactobacillus abundance and decreasing pathogenic bacteria, which is associated with better reproductive outcomes. 1, 2

  • The strain modulates both vaginal and seminal microbiomes, suggesting benefits for both partners in couples with unexplained infertility. 2

  • Uterine microbiome changes have been documented with oral L. salivarius supplementation, potentially improving endometrial receptivity for embryo implantation. 2

Immunological Effects

  • Oral administration improves both vaginal and systemic immunological profiles, which may enhance implantation success and pregnancy maintenance. 1, 2

  • The probiotic modulates the uterine immune environment, potentially creating more favorable conditions for embryo implantation. 2

Clinical Efficacy

  • Pregnancy success rates increased from 20% to 48.1% in couples with unexplained infertility who received L. salivarius CECT5713 compared to placebo before IVF. 1

  • Both pregnancy and delivery ratios improved in couples undergoing assisted reproductive treatments after 6 months of supplementation. 2


Important Caveats and Pitfalls

Product-Specific Considerations

  • Efficacy and safety findings are strain-specific and should not be generalized to other probiotic products or even other strains of Ligilactobacillus salivarius. 3

  • Verify that the product contains the specific strain CECT5713 (also known as PS11610 in some studies), as different strains may have different effects. 1, 2

  • The probiotic market suffers from inadequate regulation, with products potentially containing contaminants or lacking stated bacterial strains, so choose products with verified quality control and ATCC deposition. 4

Timing Considerations

  • Do not expect immediate effects—microbiome modulation requires at least 2-3 months of consistent supplementation. 2

  • Starting supplementation too close to the IVF cycle (less than 2 months before) may not provide adequate time for beneficial microbiome changes. 2

Conflicting Evidence

  • One study using intravaginal probiotics (not L. salivarius CECT5713) showed no benefit in recurrent implantation failure cases, highlighting that route of administration and specific strain selection matter. 5

  • The evidence base for L. salivarius CECT5713 is still preliminary, with the strongest study being a 2025 randomized controlled trial in 70 couples, so larger confirmatory studies are needed. 1

Partner Involvement

  • Consider supplementation for both partners in couples with unexplained infertility, as studies showing the best outcomes included treatment of both male and female partners. 2

  • Male partners may benefit from once-daily dosing (versus twice-daily for females in some protocols), though the optimal male dosing is less well-established. 2


Pregnancy Safety

  • Lactobacillus species are considered safe throughout pregnancy, with extensive human data showing no teratogenic effects. 6

  • If pregnancy occurs during supplementation, continuation is safe and may provide additional benefits for maintaining a healthy vaginal microbiome during pregnancy. 6, 7

  • Probiotics are compatible with breastfeeding, though most systemic antibiotics and probiotics are present in breast milk and could theoretically alter infant intestinal flora. 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Probiotic Safety and Efficacy Considerations

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Antibiotics Safe in Pregnancy

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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