The microbiome consists of all the microorganisms naturally found in the human body, including bacteria, eukaryotes, viruses, and archaea. There are several different microbial communities throughout the body ranging from the oral microbiome to the gut microbiome and more. These microorganisms play an important role in our health due to filling niches based on their location. For example, gut microbes break down foods like plant fibers that humans would normally not be able to digest.
Gut microbes also produce metabolites and neurotransmitters that impact brain chemistry and mood through a communication network known as the gut-immune-brain axis. Additionally, microbes in the oral and nasal cavities fight against bacterial colonization and adjust immune responses. If a microbiome becomes unbalanced, it is termed as being in dysbiosis and often results in negative effects (Ogunrinola et al., 2020). For instance, there are many bacterial strains naturally found in the gut that produce serotonin. If there is a reduction in the abundance of these strains, the person will have lower gut serotonin levels that influence gut-brain communication and may experience mood changes as a result.
Interestingly, scientists have suggested that the mode of delivery – vaginal versus cesarean section – may impact the baby’s microbiota composition. The uterus was previously thought to be sterile, but other studies have argued that bacteria may simply be found in lower abundance and could contribute to preterm birth (Dunn et al., 2017). Furthermore, it has been proven that the vaginal canal is dominated by Lactobacillus, a “good” bacterial genus that boosts positive outcomes. In babies delivered vaginally, the abundance of a variety of bacterial strains were found to increase in the oral and nasal cavities as well as the skin (Zhang et al., 2021).Â
Why does this matter? As aforementioned, microbiomes play important roles in digestion, neural communication, and the immune system. By understanding the implications of a vaginal delivery versus a c-section on the microbiota composition, there is an added consideration during clinical decision making. If a vaginal delivery is safe for mom and baby, this delivery method may partly be chosen to increase exposure to probiotics and strengthen the baby’s microbiota immediately once exiting the protected uterine environment. This could develop the neonate’s immune system and add protection against pathogens and c-section associated diseases.
Some studies theorize that the addition of probiotics from the vaginal canal could help develop immune tolerance mechanisms and be utilized to prevent or treat asthma and food allergies. Another potential application of these naturally transferred probiotics during vaginal birth include probiotics that reduce the risk of necrotizing enterocolitis in infants, which is a deadly infection of the intestinal wall (Zhang et al., 2021). While further research is necessary and other considerations take precedence when deciding the delivery method, the investigation of probiotic effects from vaginal childbirth is an emerging approach to treatment.
References
Dunn, A. B., Jordan, S., Baker, B. J., & Carlson, N. S. (2017). The maternal infant microbiome: Considerations for labor and birth. MCN: The American Journal of Maternal/Child Nursing, 42(6), 318–325. https://doi.org/10.1097/NMC.0000000000000373
Ogunrinola, G. A., Oyewale, J. O., Oshamika, O. O., & Olasehinde, G. I. (2020). The human microbiome and its impacts on health. International Journal of Microbiology, 2020, Article 8045646. https://doi.org/10.1155/2020/8045646
Zhang, C., Li, L., Jin, B., Xu, X., Zuo, X., Li, Y., & Li, Z. (2021). The effects of delivery mode on the gut microbiota and health: State of art. Frontiers in Microbiology, 12, Article 724449. https://doi.org/10.3389/fmicb.2021.724449