Human childbirth is an amazingly complicated process with a LOT that can, and frequently does go 'wrong'. In CA, the first-birth c-section rates range from 15% to 60%, hospital depending [0]. That's 1/6th to 3/5ths of all CA first births, let alone the obvious fact that you cannot plan a birthday. Your pregnancy can go from 'low' risk to 'life-threatening' in seconds; there is no planning for this and no hospital will tell you the bills for it.

[0] http://www.chhs.ca.gov/Press%20Releases/Smart_Care_Californi...