Why do you think God designed women to experience painful monthly cycles?

The Bible seems to imply that it may be punishment (i.e., like the pain of child birth) for Eve being the first to eat the forbidden fruit. Is this what you believe? Does that seem fair to you? The Bible specifically mentions childbirth (which may fairly include childbearing), so what is your basis for also including the painful monthly cycles in the meaning of "childbirth"?

For those of you who do not believe in the literal Adam and Eve story in which 2 specific humans disobeyed God and condemned the rest of humanity, what does the Bible tell us is the reason God designed women to experience painful monthly cycles?