I have type O- blood. DH also has O- blood and I am ABSOLUTELY postive his has been the only sperm inside me for quite awhile :LOL . I had a blighted ovum a few months ago and was told I wouldn't need "the shot" because we could offer proof that dh's blood type is O- (that was before we realized it was a blighted ovum so was irrelevant). Now I am preg. again and the mw said I would still need the first shot because there could be other "things" going on in there but after the baby was born I may not have to have the second shot. I am not sure what these "other things" could be unless she was just trying to say "just in case your dh isn't the father" but in a nice way. Does anyone know if the shot protects from something else? What do you know about "the shot" in general? Am I being stupid for checking into it and not wanting it if I don't really have to have it?