With my first pregnancy my blood tested as O- and I needed the Rhogam shot. Baby was A+ so I needed it again after birth. With this pregnancy (3 years later) my blood is testing O+ (even tested it twice) and my doctor doesn't feel I need the Rhogam shot. My mom said when I was younger she was once told I had O- blood and once told O+ blood. I am not sure how this is possible. Anyone know??? Should I be worried about not getting the shot?