Safety and efficacy support further studies
“It is widely accepted that the gut microbiome of neonates varies based on mode of delivery,” Anna K. Knight, PhD, assistant professor of gynecology and obstetrics at Emory University, Atlanta, said in an interview.
“C-sections have been associated with increased risk of asthma and metabolic disease, and have been associated with differences in the development of the immune system,” said Dr. Knight, who was not involved in the study. “There have been small pilot studies examining the use of vaginal microbiome transplants to shift the gut microbiome of neonates born by C-section to be more like the gut microbiome of neonates born via vaginal delivery, but the safety and efficacy of this treatment has not been well established. This study examines both, while also evaluating potential changes in the metabolome and neurodevelopmental trajectories.”
The current study confirmed the impact of the neonatal gut microbe on neurodevelopmental outcomes during a sensitive period, said Dr. Knight. “The fact that these differences persisted at 6 months suggests that even if the microbiome composition between vaginally-delivered and preterm infants converged at 1-2 years old, there may be lasting impacts of mode of delivery,” she said.
“The results of this study suggest that vaginal microbiome transplant may be a safe and effective way to mitigate the negative impacts of C-section delivery on the neonatal gut microbiome, and may be protective for neurodevelopment,” she added.
Regarding the Frontiers in Medicine study, Dr. Knight noted that it examined a very different population, with Zhou and colleagues focusing on Chinese infants, while Dos Santos and colleagues focused on Canadian infants.
“There was also a substantial difference in sample size between the two studies, with Dos Santos and colleagues examining > 500 more infants,” she said. “Additionally, the two studies differed in the sequencing technology used, sample collection methods, and antibiotic exposure, which can all impact microbiome study results.”
Since the current study showed efficacy and safety of VMT in a small clinical trial, larger trials with more diverse participants are needed to further examine the impact of VMT, said Dr. Knight. “The risks of vaginal microbiome transplant in mothers with infections should also be considered, and the mechanisms by which the neonatal gut microbiome impacts neurodevelopment need further investigation,” she said.
The study was funded by the National Key R&D Program of China, the Canadian Institute of Health Research, the National Natural Science Foundation of China, the Clinical Research Startup Program of Southern Medical University, China, and the Top Talent Program of Foshan Women and Children Hospital, China. The researchers and Dr. Knight had no financial conflicts to disclose.