I thought this article was so interesting:
Delivery Method Affects Brain Response to Baby’s Cry
I know that from my personal experience, I felt very detached in my mothering with my first child, who was born via c-section, when she would cry. With my second child, who was born via vbac, I couldn't tolerate hearing him cry. I would act immediately (well, most the time). I have chalked this up to the toll the difficult labor and recovery with the c-section, that it just took a lot out of me, emotionally and physically; whereas with my second, I felt victorious and energized, and I had energy to spend mothering my child.
This study is very small but I find it professionally interesting and personally gratifying to read scientific evidence for this phenomenon!