The papers in question are this one published in Pediatrics (full-text) and this more descriptive article published in the journal Gut Microbe (again full-text here) from the same author group which suggested that those born by c-section were at greater risk of developing coeliac disease. I hopefully am not going to gross out my (male) readers too much with my brief description of the c-section: an incision made in the front wall of the abdomen and womb to gain access (and give exit) to the infant, all under appropriate anaesthetic of course. Planned c-sections are not normally done under epidural or spinal block, and generally accompanied by the words "you might feel a bit of pulling and tugging" as operation 'delivering baby' commences. There are lots of different reasons for a c-section; not least multiple births (twins, triplets, etc), a breech presenting baby or in emergency cases, where for example, labour is not progressing or there is some immediate risk to the baby.
C-section born babies tend to be a little more 'baby-like' when they make an appearance because they don't have to travel through the rather cramped birth canal where they can sometimes get a bit of a 'conehead' and some bruising (which is not generally permenant I might add). One of the bonuses however of this often quite difficult journey, aside from clearing the airways, is that baby picks up quite a bit of mum on the way down in the form of various bacteria colonising the route some of which has been suggested to be protective against a few things in later life. It is with this in mind that the studies of interest have focussed on.
Getting back to those studies then. The main Pediatrics paper did the science-y bit analysing data from nearly 2000 live births. They compared the birth experience of several groups: those diagnosed with coeliac disease (CD), those with Crohn's disease, those with ulcerative colitis, those with GI disease (not otherwise specified) and asymptomatic controls free of gastrointestinal disease. There is a slightly different detail to this paper in that they use the acronym CD to denote Crohn's disease whereas I use it to denote coeliac disease.
The authors report a few important findings:
- The rate of caesarean section deliveries is on the rise (15% increase between 1991 and 2007).
- Rates of c-section delivery were elevated in CD compared with the control sample (OR: 1.83, CI: 1-18-2.85).
- Whilst breastfeeding rates were fairly similar across the groups, children with CD showed the highest rates of breastfeeding (86.6%) and for the longest period too (mean 5.18 months) despite birth by c-section being associated with a decreased likelihood of being breastfed.
- The male:female ratio was quite a bit less even across the CD group compared with the other groups (65% female).
There are a few elements of these results which are perhaps slightly counter-intuitive and have been highlighted by the study authors. The main ones being the fact that picking up mum's bacteria via a natural delivery may offer some degree of protection against CD above and beyond other inflammatory bowel diseases given the links that have been made between bacteria and such conditions. Also is the issue of breastfeeding, which despite being highest and longest for the CD group did not seem to offer very much in the way of enhanced protection against developing CD. I should perhaps add at this point that timing of gluten introduction may also have played a role here.
I have already posted on breastfeeding in relation to autism and so am not going to make too much more of this side of the data. The possible protective effects of a non c-section birth against developing CD are interesting and coincide with similar data. Other studies have for example, looked specifically at the bacterial differences between c-section and non c-section babies and reported higher levels of total gut bacteria and, in particular, higher levels of Bifidobacteria. There is also some initial evidence that certain strains of Bifidobacteria might have the ability to alter the inflammatory effects caused by gliadin (at least in the petri dish) which would fit in with the results obtained in the Pediatrics study. Added to the fact that CD is associated with perturbed Bifidobacterial colonisation, the link perhaps gets stronger (at least with regards to Bifidobacteria).
This for me is a very interesting area of research, which provides a fascinating look into how mother nature and our environment shape our very complicated lives from beginning to end. I have touched upon the concept of 'risk' before and the obvious caveat that risk is by no means equivalent to certainty. In this case, non c-section delivery reduced the risk of developing CD but so might lots of other variables, known and unknown; not least the fact that we all seem to host our own unique(?) bacterial profile influenced by lots of different things including our environment and psychology.