Restoring microbiota in newborns delivered by cesarean section

Restoration of Microbiota in Neonates - a Randomized Controlled Trial

NA · Karolinska Institutet · NCT03928431

This study is testing if exposing newborns delivered by cesarean section to their mother’s vaginal and fecal bacteria right after birth can help lower their chances of developing allergies by age two.

Quick facts

PhaseNA
Study typeInterventional
Enrollment300 (estimated)
Ages5 Minutes to 15 Minutes
SexAll
SponsorKarolinska Institutet (other)
Locations1 site (Stockholm, Stockholm County)
Trial IDNCT03928431 on ClinicalTrials.gov

What this trial studies

This study investigates the impact of exposing cesarean section (CS) delivered neonates to their mother's vaginal and fecal microbiota immediately after birth. The primary goal is to determine if this exposure can reduce the incidence of IgE-associated allergic diseases by the age of two compared to untreated CS infants. Additionally, the study will analyze the microbial community structure and immune system development in these infants over the first two years of life, comparing them to vaginally delivered infants. The findings could lead to improved health outcomes for infants at risk of allergies.

Who should consider this trial

Good fit: Ideal candidates for this study are healthy infants born via cesarean section to mothers with uncomplicated pregnancies.

Not a fit: Patients who may not benefit include those born prematurely or whose mothers have complications during pregnancy or delivery.

Why it matters

Potential benefit: If successful, this approach could significantly reduce the risk of allergic diseases in infants delivered by cesarean section.

How similar studies have performed: Other studies have shown promising results in microbiota restoration and its effects on health, but this specific approach is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Infants of healthy mothers with uncomplicated pregnancies at term, mothers of any ethnic or social background that can speak, read, and understand Swedish to the extent that they can consent in Swedish. An additional inclusion criterion for mothers in the CS groups is vaginal pH ≤ 4 at the time of birth.

Exclusion Criteria:

* Infants of mothers with pre-eclampsia or complicated pregnancies, mothers \<18 years or \>40 years of age, genital herpes simplex, genital warts, HIV, Hepatitis B or complications during delivery, infants delivered prior to 37 weeks of gestation. Additional exclusion criteria for mothers in the CS group: Mothers positive to Group B Streptococcus, Group A Streptococcus, bacterial vaginosis, vaginal pH \> 4 at the time of birth. Mothers with fecal samples positive for Salmonella, Shigella, Campylobacter or Yersinia.

Where this trial is running

Stockholm, Stockholm County

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: Atopic Dermatitis, Atopic Asthma, Immunologic Activity Alteration, microbiota, cesarean section, vaginal delivery, allergy, immunological programming

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.