Establishment of the healthy infant gut begins at birth when the infant is exposed to the microbial milieu of the mother’s vaginal canal. Consequently, the gut microbial profile of infants delivered by Caesarean section differs markedly from those delivered vaginally and may contribute to greater risk for disease in both early and later life. Evidence from a new study suggests that fecal microbiota transplantation can reset the gut microbial composition of infants born via Caesarean section to a healthier profile.

The study involved seven pregnant women (scheduled to deliver infants via Caesarean section at 37 weeks' gestation) and their infants. Each of the infants received a diluted fecal microbiota transplant derived from their own mother’s stool, delivered in 5 milliliters of their first human milk feeding. The authors of the study assessed the infants' inflammatory markers for two days in the maternity ward. Each of them women breastfed their infants for two months after the fecal microbial transplant.

During a three-month follow-up period, the infants remained healthy and showed no adverse effects. The fecal microbial composition of the treated Caesarean section-born infants showed remarkable similarity to that of vaginally born infants.

The results of this small, proof-of-concept study suggest that fecal microbiota transplantation has potential as a means of resetting the microbial composition of infants born via Caesarean-section to a healthier profile. The authors of the study cautioned that careful clinical and microbiological screening was essential to prevent serious harm to the infants.

Another player in the establishment of the infant gut microbiota is nutrition. Breastfeeding promotes a healthy gut microbial composition to confer lifelong health. Learn more about breast milk and breastfeeding in our overview article.

• Link to full study.