In recent years, developed
countries have seen an epidemic in autoimmune (type 1 diabetes, Crohns) and
allergic (asthma, allergic rhinitis, atopic dermatitis) diseases. Several
theories have been constructed to explain the sudden burst. The most notable
one is the “hygiene hypothesis,” which states that an overly clean environment
in early childhood, devoid of necessary bacteria, contributes to such diseases.
Interestingly enough, as the
epidemic of autoimmune and allergic diseases has been on the rise, so have rates
of cesarean deliveries (CD). CDs are typically performed in emergent situations,
such as breech position or decelerating fetal heart tones, however, they can
also be performed as an elective procedure at the mother’s request.
Most
research suggests that initially, the gastrointestinal (GI) tract of a fetus is
sterile. The GI tract is inoculated during and soon after birth, by bacteria
from the mother (vaginal flora) and the surrounding environment. Naturally,
this means that infants birthed vaginally will have access to more microbes for
colonization than infants born via a sterile CD procedure (although it is
important to note that the fetus is exposed to some degree of vaginal bacteria
after rupture of membranes, even if they end up being delivered by CD). Furthermore,
lactation can be delayed in mothers who undergo CDs, leaving their infants even
more deprived of the good bacteria present in breastmilk. Insufficient inoculation
of the GI tract has a negative effect on post-natal development of the immune
system; these infants are at a disadvantage when fighting off infections and
illness.
An
investigation was conducted to assess the gut microbiota of babies born at
full-term. They found that diversity differed from child to child, but patterns
of microbes were recognizable for weeks at a time. They also found a striking
similarity between gut microbiota of dizygotic twins, suggesting that
incidental environmental factors play a substantial role in inoculating intestines.
CD has been causally linked to a shift in appropriate gut microbiota and
childhood diseases, but what can we do about it? Unfortunately, scientists have decided that more research needs to be conducted to determine what
bacteria infants are still able to get from CD, and also state the need for
studies with mothers that receive antibiotics before delivery (due to positive
Group B Streptococcus status). However, some parents are taking matters into
their own hands. Michael Pollen wrote a story on this topic for the New York
Times-- in his article, he mentions a couple who, using a sterile cotton
swab, inoculated their Cesearean-delivered infant’s skin with the mother’s
vaginal secretions. A trial investigation the efficacy of this method is being
conducted in Puerto Rico. If this basic idea is deemed effective in providing infants with good bacteria, this could become a standard of care for Cesarean-delivered babies!
Sources:
2. http://www.nytimes.com/2013/05/19/magazine/say-hello-to-the-100-trillion-bacteria-that-make-up-your-microbiome.html?pagewanted=all&_r=1&
This comment has been removed by the author.
ReplyDeleteHi Tamara! I have been reading similar research regarding the hygiene hypothesis and how it effects our microbiome in our gut. I recently read an article stating that babies that are delivered through c-sections may have a decrease in Bifidobacteria and Bacteriodes and an increase in C.difficile (1). Bifidobacteria and Bacteriodes are both protective against obesity while C. difficile can cause colitis. It seems like our microbiome has a huge effect on the type of diseases that we may be predisposed to. I believe that exposing newborn babies to the mothers birth canal bacteria is a step that should be taken for all babies delivered through c-sections as there does seem to be some connection to preventing disease. Because exposing newborns to the mothers vaginal bacteria can be seen as preventative measure for disease with low risk, more research should be done in this field to see if it should be implemented as a primary treatment in all c-section babies.
ReplyDeleteSource: Musso G, Gambino R, Cassader M. 2010. Obesity, Diabetes, and Gut Microbiota: The hygiene hypothesis expanded? American Diabetes Association: Diabetes Care. 33(10):2277-2284. Available from:http://care.diabetesjournals.org/content/33/10/2277.full
Hi Tamara, what a fascinating topic! As a Cesarean-delivered baby myself, this topic hits close to home! Although my mother anticipated a vaginal delivery, a c-section saved my life (there was some sort of crisis during delivery and the interns elected for an emergency C-section). Beyond what you discuss concerning gut microbiota, c-sections have been associated with a number of other issues (http://humrep.oxfordjournals.org/content/28/7/1943), such as reduced fertility rates. In this light, both elective and non-elective c-section recipients should be well-informed of the implications for both the baby's health and the ramifications for the mother.
ReplyDeleteHey Tamara, this is a very interesting topic. Do you know if the article talks about why lactation is delayed in mothers who have undergone c-sections? My first thought would be physical and mental stress somehow mess up the mothers' hormonal secretion. Also, it would be interesting to know if babies born via c-section had an extended stay in the hospital due to their lack of microbiome protection.
ReplyDelete