the rhogam shot is given when your pregnant if you are rh(-) and after birth if you baby is rh(+). It has nothing to do with getting and staying pregnant. It's so if your baby is rh(+), it keeps the woman's immune system from producing it's own rh anti-bodies whcih would attack the baby's red-blood cells.
(I found this info on WebMD.com)
at 2:16 PM on Jul. 11, 2009