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caesarians & medical hypotheses

Many moons ago I used to do the occasional talk for Parents Centre ante-natal classes, on what to expect during a caesarian delivery. (I'd experienced an emergency C-section, so was happy to let others know what was involved.) So it was to be expected that this op.ed piece in today's NZ Herald (in the "Life & Style" section) would catch my eye. Initial interest turned to a thought that perhaps I was reading a spoof (check the date), but the paper described in this article does exist.

In January 2012 we brought together eleven researchers (midwives, scientists, epidemiologists, geneticists and epigeneticists) at the University of Hawaii and developed the EPIIC Hypothesis, which has just been published in Medical Hypothesis.

I did wonder in passing why epidemiologists & geneticists weren't counted as scientists, but what stood out is the fact the paper was published in Medical Hypotheses. (Being charitable, I'll assume the mis-spelling occurred in the editorial process.) In other words, there's no requirement to present any data in support of the hypothesis under discussion.

We have known for a while now that caesarean section is linked to longer-term health implications for the child...

As one of the commenters on the Herald piece points out, correlation is not the same as causation. Surely the researchers are aware of this?

We hypothesise that events during labour and birth - specifically the use of the synthetic hormone oxytocin, along with antibiotic use and caesarean sections - affect the epigenetic remodelling processes and the subsequent health of the mother and child.

Oxytocin is produced in large quantities during a normal labour; what would be the impact of that on epigenetic changes around the time of birth? In fact, the authors point the finger at more than (synthetic) oxytocin & C-sections, including forceps & vacuum-assisted deliveries as those potentially exerting a harmful effect. In describing this hypothesis, the op.ed. writer seems to be ignoring the fact that in at least some cases not using those interventions could result in the considerably more harmful outcome of death for mother &/or child. (To be fair, things are narrowed down somewhat in the MH paper.)

In the EPIIC hypothesis, we propose that physiological labour and birth have evolved to exert eustress (a healthy, positive form of stress) on the fetus, and that this process has an epigenomic effect on particular genes, particularly those that programme immune responses, genes responsible for weight regulation, and specific tumour-suppressor genes.

This is an interesting use of the term 'eustress', since its definitions suggest that whether or not stress is 'healthy' depends on how the individual perceives that stress, & whether they are left with a 'feeling of fulfilment' after experiencing it. At what point would a 'normal' labour cease to be so, & start generating 'non-healthy, negative' forms of stress? 

And how would this hypothesis be tested? The Medical Hypotheses paper (sorry; it's behind a paywall) does suggest a possible research program: essentially a long-term project tracking outcomes in individuals who birth experiences range from 

home births in the most familiar environment to the woman and without medical interventions ... to those born after elective caesarean section for breech presentation where there are no underlying medical complications...

and including

various ethnic groups, gestational ages, maternal ages and socioeconomic backgrounds.

With so many variables listed, proper data collection & analysis would be an extremely complex task. There is no mention of how this might be properly blinded. And - as that same Herald commenter says - why not go for an animal model first? And publish the results in a mainstream journal?

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4 Comments

we propose that physiological labour and birth have evolved to exert eustress (a healthy, positive form of stress) on the fetus

Lagercrantz and Slotkin were on the case a quarter-century ago.

I was so hoping that the Herald piece was an April Fool's spoof. So sad to find otherwise :(

It's a curious approach, you'd think you'd at least first determine if there was a difference in children from caesarean section births compared to those that weren't before suggesting what might cause a difference that you haven't yet found. (Or perhaps I'm missing something?)

Some of the references they cite do suggest that there might be some differences. But one of those studies was looking at the likelihood that a child born by C-section to parents with eczema would also have eczema - if there's any genetic underpinning to atopy then it's going to cloud any possible relationship with delivery mode. Also, at least some C-sections are prem deliveries, & children in that cohort may have a higher likelihood of eg respiratory issues, again regardless of delivery mode.

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  • Alison Campbell: Some of the references they cite do suggest that there read more
  • Grant: It's a curious approach, you'd think you'd at least first read more
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  • herr doktor bimler: we propose that physiological labour and birth have evolved to read more