Found this article today, a research publication on cell migration from fetus to mother. It explains that in some conditions when a mother is threatened by organ damage, the fetus will send its stem cell to the damaged area and repair it. As the fetus survival is at stake when a mother suffer from organ damage, it is not very suprising to know this stem cell transfer process actually happened.
Come to think of it, perhaps this how the Sleeping Beauty (from the original story, not the Disney one) finally wake up after her long period of sleep/vegetative state. She was poisoned then left alone in the woods, taken care of by forest fairies. The poison probably caused severe damage to her internal organs, and some part of her brain hence she fall into vegetative state (semi dead/sleeping).
In this period of vegetative state, somebody found her and raped her. The rape gave her twin children. For their survival during conception, the twin children release stem cells to the damaged area in her body. She finally wakes up when the repairs are done, and blablabla lived happily ever after with her rapist and children. Kind of dark.
Never thought Sleeping Beauty can be this scientific.