Having a blood clot or a heart attack or an epileptic fit is also "a natural thing". It happens naturally. Lots and lots of illnesses are "natural things". Natural isn't always Nice. Without intervention, sometimes people survive these events. Sometimes they don't. Sometimes they survive but are left in a greatly weakened or disabled state. Childbirth is also a natural event which happens naturally. And sometimes people survive and sometimes they don't and sometimes they survive but are left in a greatly weakened or disabled state. We intervene medically to improve people's chances of surviving strokes and heart attacks and epileptic fits, rather than "letting the normal process unfold." So why not intervene medically to improve someone's chance of surviving childbirth?