Answer:
"Jehovah's Witnesses believe that it is against God's will to receive blood and, therefore, they refuse blood transfusions, often even if it is their own blood. The willing acceptance of blood transfusions by Jehovah's Witnesses has in some cases led to expulsion from and ostracisation by their religious community."
Step-by-step explanation:
I'm Catholic but this is what I read on what they believe for blood transfusions. Also, this blood transfusion happened to a singer named Selena, she died because she couldn't get a blood transfusion because of her Religion.
Hope This helped. Sorry if it's wrong.