This was an article shared a while back on Fran's blog over at Small Bird Studios. The article explains how one doctor feels that when women are pregnant that a portion of the baby's cells are forever in the body of the mother. They are to believed to provide protection for the mother.
For me, this is comforting that Sam and Michalina are with me forever-no matter what. I have a part of them with me and they have formed who I am today.
Take a look at the article here. It is worth reading and not very long.