The answer is scheduled C-sections and if you haven't read it, Atul Gawande's 2006 New Yorker article on why they've become so common is good read: https://www.newyorker.com/magazine/2006/10/09/the-score After watching The Business of Being Born , Gawande's article was really helpful in understanding why things are done the way they are.
In retrospect, this guy is practically the prototype of villain in healthcare. He's Eric Lander levels of villainy.
He shouldn't be considered a credible voice just out of corruption. There are many doctors who can write.
Consider his role at Partners (now "Mass General Brigham"): overseeing the growth of a notoriously money grubbing institution, run anticompetitively, despite the excellence of its providers. He has parlayed... saucy New Yorker writing into becoming the very hospital administrator who is responsible for all the fuckups he shits on.
Trust me, if he has something to say about, I don't know, fucking childbirth, it has been known to everyone for years. The difference is his presence in The Magazine New Yorkers Care About lets him omit anything shitty to say about himself and his Partners.