what an odd coincidence to see David Haig mentioned in the article. I just stumbled over his interview on Sean Carroll's podcast a few days ago, discussing the exact same topic (https://www.preposterousuniverse.com/podcast/2020/11/30/125-...)

"And so while the cooperative outcome would be the most efficient, you lead to a situation in which there are conflict costs, and I think this explains why things go wrong so often during pregnancy. Of course, at first sight it's strange, my heart and my liver have been functioning very well for for 62 years, and yet during pregnancy, you have a natural process that only lasts for nine months, and yet many things go wrong during it. And I would argue that the reason why pregnancy doesn't work as smoothly as the normal functioning of the body is that in normal bodily functioning all the parts of the body are genetically identical to each other and working towards survival of that body, but in pregnancy, you have two different genetic individuals interacting with each other and natural selection can act at cross-purposes, there's a sort of politics going on, and we know that politics does not always lead to efficient outcomes."