Caesarean section helps in difficult births, mostly where babies cannot fit through its mother’s pelvis. According to studies we have embraced this method in ever increasing manner from last 6 decades, and now this has caused the babies to be bigger than before. Bigger babies are healthier but they had size restriction due to regular birth through vagina. Is it possible that due to C -section, size of the babies are increasing?
How could evolution be happening so fast – doesn’t it take millennia? Not necessarily – evolution can happen over a single generation if the environmental changes are drastic enough. In the case of C-sections, we may have had two or three human generations since they became more common in the 1950s.
Haven’t C-sections risen by more than that anyway? Yes, the C-section rate is now about 25 per cent in the UK. So even if evolution is having an effect, it would be hard to disentangle from all the other factors driving the rise in C-sections.
And aren’t women just too posh to push these days? Actually, some doctors argue there’s a reasonable medical case for avoiding a vaginal birth, which carries a 90 per cent risk of a tear or cut to the genitals and over a 5 per cent risk of tearing through the anus in a woman’s first birth. In the UK, women are now supposed to be allowed to choose C-sections without medical reasons, as long as they are told about the risks of surgery, which include infection and blood loss.
How do we know if it’s happening?
Mitteroecker’s team hasn’t produced any evidence that it is. The study was theoretical work, based on plugging observed figures for the rate of obstructed childbirth into their models. Their predicted rise of 20 per cent is still quite small, though – it would have taken the rate of obstructed births from 3 per cent, a conservative estimate for the rate before C-sections, up to 3.6 per cent today.
So how will we know if evolution really is affecting the C-section rate?
We won’t. But Mitteroecker says the idea is something to consider in discussions about the “right” level of C-sections, because most assume the number of obstructed births is constant. And natural childbirth proponents who urge women to “trust birth” might also want to bear it in mind.
This article was first published on newscientist.com