I found out today that I am Rh negative too, they told me that they assumed the father was positive (because most people are-and he is because we happen to know his blood type) and that I would receive two shots throughout the course of the pregnancy. They said the shots were to prevent antibodies from building in my system in response to the baby being positive and me being a negative blood type. They also told me that it really has no affect on this baby, but would affect future pregnancies if I did not receive the shots (the antibodies would be in my system and would attack any future pregnancies).