The Hansel and Gretel thing is the only thing making me question if she actually could have wanted to get pregnant in FTL. If she wanted to prevent getting pregnant with either Leopold or Graham, I’m sure she could have easily arranged that. Modern world contraception isn’t the only form of birth control there’s ever been, so I’m sure they had condoms of some description in FTL, but even if not, Regina could have magiced herself up some contraception.
Maybe by the H and G incident she was already too far gone into the Evil Queen mode. It took Owen and realizing that she wanted a real new life for all to click. She does tell Kurt, “what’s the point of a fresh start if you have no one to share it with?” So with H and G, she realized that maybe she does want kids or a family, but she wants it HER way, for them to forsake their father. Then when they reject her, she moves further into the EQ mode. Then Owen happens and that old desire is awakened, but this time she’s screwed because of the Curse.