C-section Babies Differ in Microbial Communities

C-section delivery results in 'abnormal' microbial seeding of the infant and 'abnormal' development of immunity due to the lack of exposure to the vaginal microbiota. Negative outcomes connected to C-section deliveries have been shown to include as obesity, asthma, allergies, type 1 diabetes, food allergies, eczema, and celiac disease. C-section babies don’t have the full exposure to the mother's microbiota compared to the vaginally-delivered babies. During labor the baby is rubbing against the mucosa of the birth canal for a long time and bacteria start growing even before the baby is out — growing and colonizing the baby during birth. In half an hour, you get multiplication of bacteria. If the baby gets one bacterial cell, an hour later the baby has probably four of those cells and five hours later even more; it’s exponential growth. The microbiota in a baby’s first stool closely resembles the mother’s vaginal microbiota for vaginal delivery, whereas with C-section delivery, the baby’s first stool microbiota closely resembles the mother’s skin microbiota.

Lost Microbial Relationships

Higher concentrations of Lactobacillus, a kind of bacteria capable of fermentation and production of lactic acid, are found in a healthy woman's vagina. A C-section baby will miss out on immediately acquiring these beneficial bacteria, and this can cause differences even 7 years after delivery. Gut colonization by microbes and immune development are different in C-section infants, which may explain in part why these infants have a harder time fighting off infections. Dutch researchers recently published a study showing that infants with colic have more bacteria that are known to produce gas, whereas anti-inflammatory bacteria that live in the vaginal canal are more common in colic-free infants.

Questions Waiting to be Answered

"There is no C-section without antibiotics, and we don’t know what the effect is of that gram of penicillin. If it’s good enough to kill strep B, I’m sure it’s killing a lot more than that community of bacteria." - Dr. Maria Gloria Dominquez-Bello.

Medical interventions like C-sections and antibiotics are prescribed for very good reasons. However, what current microbiome research is trying to understand is related to the types of bacteria/community patterns that are indicative of when these interventions have a detrimental effect. Dr. Elizabeth Costello of Stanford is doing research on what the newborn microbiome looks like at the end of two years comparing vaginal births (bacterial genus called Bacteroides is in abundance) versus C-births (Bacteroides are nearly missing).  Questions that will hopefully be answered are: Do the Bacteroides species decrease for vaginal births, do Bacteroides levels increase for C-Section births, and do the differing birth methods normalize and approach other? This study is also looking at antibiotic use relative to recovery of the gut microbiome since almost half of the infants have had at least one antibiotic hit. They are looking to learn:  Are there reduced numbers of beneficial bacteria and is recolonization to a normal microbial community impeded?

In addition, researchers are looking to exploit situations where alternative solutions can be explored. For instance, could antibiotics can be prescribed less often or paired with adjunct therapies such as probiotics, or is it possible that C-section babies could have artificial microbiota inoculations. There is clinical research that is attempting to artificially restore an inherited mother's microbiota in four C-section newborns by inoculation with a gauze that has been inserted in the vaginal canal for one hour prior to Cesarean birth.  These infants were then followed for one year to see if their microbiota normalized.  The preliminary data: the four C-section babies at four months seem to have acquired the mother’s vaginal microbiota, and their microbiota is beginning to look more like that of a natural vaginal birth.