Impact of vaginal bacteria on pregnancy success after embryo transfer

The Influence of the Vaginal Microbiome on Clinical Pregnancy in Patients Undergoing a Euploid Embryo Transfer: a Prospective Blinded Multicentre Cohort Study

Observational Fundación IVI · NCT06643065

This study is trying to see if the types of bacteria in the vagina affect the chances of getting pregnant after an embryo transfer for women undergoing fertility treatments.

Quick facts

Study typeObservational
Enrollment1573 (estimated)
Ages18 Years to 50 Years
SexFemale
SponsorFundación IVI Academic / other
Locations10 sites (Barcelona, Barcelona and 9 other locations)
Trial IDNCT06643065 on ClinicalTrials.gov

What this trial studies

This observational study aims to investigate the relationship between the vaginal microbiome and clinical pregnancy outcomes in women undergoing euploid embryo transfers. By analyzing the presence of specific vaginal bacteria, the study seeks to determine if an imbalance in these microorganisms correlates with pregnancy failures. The findings could lead to recommendations for routine microbiome testing in fertility treatments, allowing for potential interventions to restore a healthy vaginal environment. The study is conducted across multiple centers to gather a diverse patient population.

Who should consider this trial

Good fit: Ideal candidates for this study are women undergoing assisted reproductive technology (ART) with the transfer of a euploid embryo.

Not a fit: Patients with significant uterine abnormalities or those who have recently taken antibiotics may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved pregnancy outcomes for women undergoing fertility treatments by addressing vaginal microbiome imbalances.

How similar studies have performed: While the relationship between the vaginal microbiome and pregnancy outcomes is being explored, this study represents a novel approach in this specific context.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* ART patients undergoing the transfer of a euploid embryo

Exclusion Criteria:

* Patients with a body mass index (BMI) ≥35

  * Patients with uncorrected uterine malformations
  * Patients with a unicornuate uterus
  * Patients with a bicornuate uterus
  * Patients with any type of submucosal myoma
  * Patients with an intramural myoma if ≥4 cm
  * Patients with severe adenomyosis (\>50% of the uterine corpus affected as defined by the MUSA criteria \[19\])
  * Patients undergoing transfer of an embryo with a morphology score \<4BC (according to the Gardner \& Schoolcraft scoring system \[18\])
  * Patients undergoing transfer of a day-7 embryo
  * Patients who took antibiotics in the month prior to the embryo transfer (excluding antibiotics given following oocyte retrieval)

Where this trial is running

Barcelona, Barcelona and 9 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Vaginal MicrobiomeFemale reproductive tract microbiome,Vaginal dysbiosis
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.