Personally I think that she either got pregnant to someone high up or that the baby was given to a childless couple who have registered the baby in another name.
This still makes no sense. So many possibilities. On one hand I don't think she would've done anything sinister to the baby but on the other hand surely she would confess to giving the baby away by other means.
This is what I always come back to, and why I think she's guilty.
I can't think of plausible explanations where she'd sit in prison for 15 years to protect people for (relatively) minor crimes.
Add that to the enormous holes in her story and I always come back to the same conclusion: guilty.