Rubbing newborns by caesarean section with vaginal fluids from the mother to transfer their bacteria to them seems to benefit the early development of babies and the formation and maturation of their own intestinal microbiota. This is clear from a study published today in Cell Host
Babies born by caesarean section often have a different intestinal flora composition than those born vaginally, who begin life with a greater abundance of Lactobacillus and Bacteroides. This is so because babies born vaginally receive their first intestinal bacteria through the mother's birth canal, while the microbiota of those born by cesarean section is colonized by bacteria characteristic of the mother's skin or present in breast milk and in the environment.
And although these differences tend to disappear with age, the researchers believe that this early microbiota affects the development of immunity in the child and their risk of getting sick or developing pathologies such as diabetes later on. Population and animal studies have shown that the microbiome plays a crucial role in immunological and neurological development in the first years of life, and there is increasing scientific evidence of the close link between the gut and the brain.
"There are several epidemiological studies that show that birth by cesarean section is associated with a higher risk of later developing certain diseases, especially immune-related diseases such as allergies; our working hypothesis is that this risk associated with cesarean delivery is partially determined by the colonization of the baby by harmful bacteria, which leads to a destabilization in the production of metabolites that are necessary for the proper development of the baby," explains José C. Clemente, professor and researcher at the Mount Sinai School of Medicine, by email. in New York and one of the study authors.
Hence, they decided to test whether it was effective and safe to transfer the vaginal microbiota from the mother to babies born by cesarean section by other means and what effects this intervention had on the phenotype of the babies, for example on their neurodevelopment, according to the lead author. of the work, Yan He, of the Suthern Medical University in Guangzhou (China) in a statement.
To do this, the group of researchers rubbed the lips, skin and hands of 32 newborns by cesarean section with gauze soaked in their mother's vaginal fluids while rubbing another 36 with a saline solution to serve as a control group. . And stool samples were collected 3, 7, 30 and 42 days after all of them and another 33 born through the vaginal canal to compare both their microbiota and their metabolome, the metabolites present in it. In addition, their neurodevelopment was measured at three and six months through a questionnaire to the mothers about different actions that the baby was capable of performing.
And they found significant differences both in the bacteria that colonized their intestine and in their capacities.
"We observed above all an increase in Lactobacillus in babies impregnated with vaginal fluids, although there is also an enrichment in the acquisition of Escherichia and Bifiobacteria", summarizes Clemente.
And he explains that the presence of Lactobacillus means that there is an effective transfer of vaginal fluids and the accelerated acquisition of Eschericia and Bifidobacteria could indicate that the microbiome of these babies is following the same development patterns as those born vaginally. "That is, we are reproducing what happens in vaginal delivery," she says.
In the control group, on the other hand, they observed a persistence of Klebsiella, a bacterium that in previous studies has been associated with pro-inflammatory responses in the organism and a lower production of neuroprotective molecules.
Added to these differences in bacterial flora are others observed in neurodevelopment. "Both at three and six months, a significant improvement is observed in the group of babies impregnated with vaginal fluids compared to the control group, particularly with regard to their communication skills and motor skills", details the researcher from the School of Medicine at Mount Sinai.
They also detected several differences in the metabolite profiles of each group. Children soaked in vaginal fluids had more lactic acid and GABA, an important neurotransmitter, which could explain part of the improvement in their neurodevelopment.
On the other hand, Clemente says, despite having exposed the newborns to bacteria, "we did not observe an increased risk associated with exposure to vaginal fluids compared to the control group," so the intervention is considered safe in addition to beneficial.
The experiment was so-called triple-blind, that is, neither the participants nor the researchers and evaluators knew who had undergone the intervention and who was the control group, which gives greater robustness to the evaluation of the results.
However, the researchers acknowledge that the sample on which they have carried out their study is small and it will be necessary to carry out larger studies to confirm these results and that this type of intervention is incorporated into the usual clinical practice of cesarean deliveries.
