Transplantation of maternal intestinal flora to the newborn after elective cesarean section (SECFLOR): study protocol for a double blinded randomized controlled trial

BACKGROUND: A complication of elective cesarean section (CS) delivery is its interference with the normal intestinal colonization of the infant, affecting the immune and metabolic signaling in early life— a process that has been associated with long-term morbidity, such as allergy and diabetes. We evaluate, in CS-delivered infants, whether the normal intestinal microbiome and its early life development can be restored by immediate postnatal transfer of maternal fecal microbiota (FMT) to the newborn, and how this procedure influences the maturation of the immune system. METHODS: Sixty healthy mothers with planned elective CS are recruited and screened thoroughly for infections. A maternal fecal sample is taken prior to delivery and processed according to a transplantation protocol. After double blinded randomization, half of the newborns will receive a diluted aliquot of their own mother’s stool orally administered in breast milk during the first feeding while the other half will be similarly treated with a placebo. The infants are clinically followed, and fecal samples are gathered weekly until the age of 4 weeks, then at the ages of 8 weeks, 3, 6, 12 and 24 months. The parents fill in questionnaires until the age of 24 months. Blood samples are taken at the age of 2–3 days and 3, 6, 12 and 24 months to assess development of major immune cell populations and plasma proteins throughout the first years of life. DISCUSSION: This is the first study to assess long-time effects on the intestinal microbiome and the development of immune system of a maternal fecal transplant given to term infants born by CS. TRIAL REGISTRATION: ClinicalTrials.gov NCT04173208, registration date 21.11.2019. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03609-3.