Investigating the microbiome's effect on pregnancy outcomes in women planning to conceive

Impact of the Microbiome on Time to Pregnancy and Pregnancy Outcomes in Fertile Women Attempting to Conceive

Karolinska Institutet · NCT05127252

This study is trying to see how the bacteria in the body affect pregnancy outcomes for women who have given birth before and are planning to get pregnant again.

Quick facts

Study typeObservational
Enrollment500 (estimated)
Ages18 Years to 40 Years
SexFemale
SponsorKarolinska Institutet (other)
Locations2 sites (Stockholm, Huddinge and 1 other locations)
Trial IDNCT05127252 on ClinicalTrials.gov

What this trial studies

This observational study aims to explore the role of the microbiome in women who have previously given birth and are planning to conceive again. Participants will be recruited at midwife clinics in Stockholm, Sweden, at the time of contraceptive device removal. A total of 500 women aged 18-40 will be followed for up to one year or until conception, with additional monitoring throughout pregnancy if conception occurs. The study will analyze vaginal and rectal microbiome and metabolome samples to assess their impact on fertility and pregnancy outcomes.

Who should consider this trial

Good fit: Ideal candidates are women aged 18-40 with a previous live birth in the past 5 years, planning to conceive with the same partner.

Not a fit: Women who have not had a child yet and plan to stop contraception will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could enhance understanding of how the microbiome influences fertility and pregnancy outcomes, potentially leading to improved reproductive health strategies.

How similar studies have performed: While the role of the microbiome in fertility is an emerging field, similar studies have shown promising results, indicating potential for significant insights.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Women with a previous live birth in the past 5 years and planning a new pregnancy with the same male partner.
* 18-40 years of age
* Swedish personal identity number and a Swedish address (to send a sampling self-kit)
* Sufficient understanding of spoken and written Swedish or English to provide informed consent and complete the web-based questionnaire.

Exclusion Criteria:

* Women who do not have a child yet and plan to cease their contraception.

Where this trial is running

Stockholm, Huddinge and 1 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.

View on ClinicalTrials.gov →

Conditions: Pregnancy Complications, Contraception, Pregnancy Loss, Fertility, Microbial Colonization, Metabolome, cohort, fertility

Last reviewed 2026-05-15 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.