Has anyone ever experienced or have any knowledge of this topic? It's rare and I can't even find any information at all. The Dr. Didn't have much info for me either! At 12 wks part of the placenta went into and filled my cervix! The baby is still in my uterus in the rest of placenta and heartbeat is strong, but the doctor says there is nothing they can do and that I will miscarry. I wish I could get more info about this?