Part of this is the curse... for women had never given birth before... but I imagine that had Adam and Eve not sinned... it would have not been painful or labored.
Easy peasy
As I re-read this verse and pray about the answer, I believe that in the garden, even though they were one flesh God ruled over them both (Adam and Eve). But when they sinned... God ordained man as the head of the house and the womans desire was to serve her husband and not just be a helpmate or equal partner and seeker of the Lord.
It's like God was setting or ordaining the man to be the priest of each house. We today have no idea how it was in the garden, we only know how it became, and the desire for a lot of women is for her husband and family. This verse is just our seeing God speak into existence what most of us already feel inside.
Hope this helps
Blessings