Wasn't Meloni a Thawne? I thought her crazy prez dad was experimenting on her with Velocity 9 or something, but they couldn't figure out why she wasn't getting any faster. They didn't know she was pregnant.
...or maybe I read that in a fan-theory somewhere. It sounds plausible enough to me, though. Of course, if it is a fan theory, DC probably couldn't come up with a more workable story if you paid them. Which we do.