Because Eve made us all evil women, that's why. /sarcasm

Apparently someone took the verse that says women shall bring forth children in pain, and in the medieval period (I think) this was translated to women had to suffer.

Also, remember, much of the time births were attended by midwives, and we all know how suspicious those women with their herbal knowledge are. They might use (gasp) witchcraft.

Queen Victoria's use of chloroform made the whole thing much more acceptable.

DV