Writing is Rewriting

I know this old saying is true, but revising a novel that's over 400 pages is no small task. Touch a detail in one chapter and you may have effected a dozen others. For example, my main character's miscarriage is going to come later and become more of a turning point, but delaying it means I have to watch for times when I had her drinking coffee at playgroup. Now she'll have to keep drinking decaf for awhile. It sounds trivial, but it's the kind of thing that, should I miss it, will look amateurish.