well i was in the ER yesterday and they gave me a Rhogam shot but didnt explain it that well. all they told me was that it was because i was A- and RH- and that the baby could be RH+ but they didn't explain it that well can any1 help explain it.

I found this to be the best description.
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During any pregnancy a small amount of the baby's blood can enter the mother's circulation. If the mother is Rh negative and the baby is Rh positive, the mother produces antibodies (including IgG) against the Rhesus D antigens on her baby's red blood cells. During this and subsequent pregnancies the IgG is able to pass through the placenta into the fetus and if the level of it is sufficient it will cause a Rhesus D positive fetus to develop Rh disease. The mechanism is maternal anti-D IgG passing through the placenta to the fetus causing destruction of fetal red blood cells. Generally Rhesus disease becomes worse with each additional Rhesus incompatible pregnancy.

The main and most frequent sensitizing event is child birth (about 86% of sensitized cases), but fetal blood may pass into the maternal circulation earlier during the pregnancy (about 14% of sensitized cases). Sensitizing events during pregnancy include miscarriage, therapeutic abortion, amniocentesis, ectopic pregnancy, abdominal trauma and external cephalic version.

It is very rare for the first Rhesus positive baby of a Rhesus negative woman to be affected by Rh disease. The first pregnancy with a Rhesus positive baby is significant for a rhesus negative woman because she can be sensitized to the Rh positive antigen. If it were not for modern prevention and treatment, about 5% of the second Rhesus positive infants of Rhesus negative woman, would result in still births or extremely sick babies and many babies who managed to survive would be severely ill. Even higher disease rates would occur in the 3rd and subsequent Rhesus positive infants of rhesus negative woman. By using anti-RhD immunoglobulin (Rho(D) Immune Globulin) the incidence is massively reduced .

Prevention
Most Rh disease can be prevented by treating the mother during pregnancy or promptly (within 72 hours) after childbirth. The mother has an intramuscular injection of anti-Rh antibodies (Rho(D) Immune Globulin), so that the fetal Rhesus D positive erythrocytes are destroyed before her immune system can discover them. This is passive immunity and the effect of the immunity will wear off after about 4 to 6 weeks (or longer depending on injected dose) as the anti-Rh antibodies gradually decline to zero in the maternal blood.

It is part of modern antenatal care to give all Rhesus D negative pregnant women an anti-RhD IgG immunoglogbulin injection at about 28 weeks gestation (with or without a booster at 34 weeks gestation). This reduces the effect of the vast majority of sensitizing events which mostly occur after 28 weeks gestation. Anti-RhD immunoglobulin is also given to non-sensitized Rhesus negative women immediately (within 72 hours - the sooner the better) after potentially sensitizing events that occur earlier in pregnancy.
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So basically what the shot is supposed to do is like neutralize the RH factors so your body won't produce antibodies to cross the placenta in your current pregnancy and in future preganancies to attach the baby's red blood cells should that baby have a possitive RH factor.

Hope this info helps.

thanks that helped a lot i was reading on the net that the shot could also hurt the baby is that true at all?

I don't know about that. That would be a question for your doctor. But I know that this is a common thing that pretty much all doctors check for and give, so I would think that if there is a possibility of the shot harming the baby that the positives of the shot outweight the negatives of the shot.

well thanks so much that helped a whole lot thanks