I too am Rh- (O-); the anti-D injection is called Rhophylac. This injection contains a medicine called human anti-D immunoglobulin. It is given to pregnant women who have a blood type known as rhesus negative. People whose blood type is rhesus positive (RhD positive) have a substance called D antigen on the surface of their red blood cells. People whose blood type is rhesus negative (RhD negative) are missing this antigen. Whether a person is rhesus positive or rhesus negative is determined by their genes. Having a rhesus negative blood type is not usually a problem. However, if a rhesus negative woman is pregnant and her baby is rhesus positive it may cause problems.If blood cells from a rhesus positive baby get into the rhesus negative mother's bloodstream, her blood will react as if the baby’s blood is a foreign substance and will produce antibodies against it. This is not usually a problem in a first pregnancy with a rhesus positive baby. However, the antibodies that the mother produces stay in her blood, and if she has another pregnancy with a baby who is also rhesus positive, her antibodies can cross the placenta and attack the blood cells of the unborn baby. This can cause 'haemolytic disease of the newborn'. Haemolytic disease of the newborn can be very mild, but in a small number of babies it can be more serious and cause the baby to be stillborn, severely disabled or to die after birth as a result of anaemia and jaundice.The most common time for a baby's blood cells to get into the mother's blood, causing her to produce antibodies, is at the time of birth. However, this can also occur at other times, for example during a miscarriage or abortion, or as the result of having an amniocentesis, chorionic villus sampling, vaginal bleeding, or turning the baby’s head down (external cephalic version). These events are called 'potentially sensitising events'. To prevent rhesus negative women producing antibodies against their baby’s blood during pregnancy they can be given an injection with anti-D immunoglobulin. This treatment is called anti-D prophylaxis, and prevents the mother's immune reaction that could cause haemolytic disease of the newborn.Anti-D prophylaxis is offered routinely to pregnant women who are rhesus negative, usually at weeks 28 and 34 of their pregnancy, unless they already have anti-D antibodies in their blood. (This is tested by a blood test at the start of the pregnancy.) The treatment is offered regardless of whether a sensitisation event has occurred, in order to be absolutely certain that the mother does not develop antibodies against the baby. After the birth, a blood sample will be taken to test the baby's blood group. If the baby is rhesus positive, the mother will be given a further injection of anti-D immunoglobulin. (This is called postnatal anti-D prophylaxis.) Anti-D immunoglobulin will also given after any sensitising event that occurs during the pregnancy. Anti-D prophylaxis may not be necessary for rhesus negative mothers if there is certainty that she will not have another child following the pregnancy, for example if she is to be sterilised after the birth. It will also not be necessary if the father's blood type is also rhesus negative, as genetically this means the baby cannot be rhesus positive. Anti-D immunoglobulin may also be used if a rhesus negative individual is given a blood transfusion of rhesus positive blood, to prevent the individual forming antibodies against the transfused blood.
When I was in the 28th week of my pregnancy (in 1996) I was given the RhoGam injection. RhoGAM is a medical treatment that has nearly eliminated the risk of jaundice, hypotonia, and motormental retardation from Rh incompatibility between a mother and fetus. Rh incompatibility occurs when a woman without the Rh factor (a protein found on the red blood cells of most people), conceives a child who has the Rh factor. The mother's Rh negative blood will react against the Rh positive blood of her fetus and attack it with antibodies.
The RhoGAM injection halts the mother's immune system from responding to the Rh positive blood of her child as a foreign threat and attacking it with antibodies. RhoGAM is a preventive drug and in its current form offers huge benefits with very minor side effects.