A Randomized, Blinded, Controlled Trial to Evaluate Effects of Multi-strain Bacillus Spore Probiotic Supplements (LiveSpo PREG-MOM and LiveSpo CONSY) on Growth Metrics, Prevention of Functional Gastrointestinal Disorders, and Modulation of the Gut Microbiota in Cesarean-Delivered Neonates

Infants delivered by cesarean section commonly experience early differences in feeding and distinct patterns of gut microbial development compared with infants born vaginally. Because cesarean delivery limits contact with maternal vaginal microbiota, which is an important source of early microbial transfer, these infants often show delayed establishment of key early colonizers. Multiple cohort studies have documented lower abundances of beneficial genera such as Bifidobacterium and Bacteroides, along with relatively higher proportions of Proteobacteria during the first months of life. This shift in microbial composition has been associated with functional gastrointestinal symptoms in early infancy, including regurgitation, colic, abdominal discomfort, and changes in stool frequency and consistency. Such symptoms can affect feeding patterns, contribute to variations in weight gain, and influence overall gastrointestinal functioning during the neonatal period. As cesarean delivery rates continue to rise in Vietnam, there is increasing interest in supportive approaches that may help promote gastrointestinal functioning and healthier gut microbial development in this group.

Probiotic supplementation during early infancy has been explored as a potential strategy to support gut microbial maturation. Spore-forming Bacillus strains, belonging to safe B. subtilis, B. clausii, and B. coagulans species, are notable for their stability and ability to survive passage through the digestive tract. These characteristics allow them to reach the intestine in viable form, where they may interact with the developing gut ecosystem. Prior pediatric studies of Bacillus preparations have reported favorable safety profiles and signals of benefit for digestive conditions, although findings vary depending on strain and study design. Multi-strain products may offer complementary biological functions, providing broader support for the developing gut environment.

Based on this scientific background, the present study has been designed to evaluate two oral Bacillus spore probiotic formulations of B. subtilis ANA46, B. clausii ANA39, and B. coagulans ANA40, LiveSpo PREG-MOM (3 billion spores per 5 mL) and LiveSpo CONSY (4 billion spores per 5 mL), in cesarean-delivered infants. The study aims to evaluate whether daily supplementation during the first 90 days of life influences early growth trajectories, the occurrence of functional gastrointestinal disturbances, immune indicators in stool, and the development of gut microbial communities. The study will also assess the presence of probiotic spores in stool as an indicator of product use compliance.

This investigation is a randomized, blind, controlled clinical trial conducted at Hanoi Obstetrics and Gynecology Hospital. A total of 180 healthy full-term infants (38-40 weeks' gestation) delivered by cesarean section will be enrolled after parental consent. Eligible infants will be randomly assigned in equal numbers to one of three groups: Placebo (RO water), Pregmom (LiveSpo PREG-MOM), or Consy (LiveSpo CONSY). Randomization will use permuted blocks to help maintain balanced allocation across groups, and all products will be provided in identical coded ampoules to ensure blinding of families, clinical staff, and laboratory personnel.

Participants will receive one 5-mL ampoule of the assigned product once daily for 90 days. Clinical assessments will be performed at baseline and on days 2, 9, 30, 60, and 90. These assessments include measurements of weight, length, and head circumference, along with documentation of digestive patterns such as stool frequency, stool characteristics, regurgitation…, using structured observation tools suitable for young infants.