At your initial appointment, there are many base-line blood values that are needed to be obtained to help monitor and plan your care during your pregnancy. Many patients come in to the office unsure of their blood type or sure that their mom told them something important to remember about her blood-type and they don't know what it is. Chances are it's about the Rh factor.
Your blood type will be reported as either O, B, A or AB and either positive or negative. You inherit your blood type genetically, from your parents. If your blood type is O, B, A, or AB positive, there is no need to read on, unless you just want information.
The issue is with a negative Rh factor. If your blood tests negative, then your partner needs to be tested for his Rh factor. If a mom has a negative Rh factor and a dad has a positive, the baby has a chance of inheriting the dad's positive blood Rh factor. Moms with Rh factor negative may have an immune response to a baby's Rh positive blood cells that have mingled ( as blood cells do )with her blood cells. Since this important difference is recognized by the mom's body as dissimilar from her own, her body will produce antibodies to get rid of the positive Rh blood cells that are now in her circulatory system. This immune response and the creation of antibodies can destroy not only baby's cells circulating in mom's blood stream but also, since the antibodies can cross the placenta, the antibodies are capable of destroying baby's own blood cells.
This is of great significance with pregnancies usually other than a first ( subsequent ) and when there has been a co-mingling of blood that can occur with bleeding in pregnancy: miscarriage, termination, amniocentesis, version and ectopic pregnancies. It can also happen as a result of a blood transfusion.
As mom's body creates more and more of these warrior antibodies, baby loses more and more red blood cells which can lead to anemia in the baby. This complication can be very seriously dangerous and must be identified and avoided. The severe jaundice that may result from this incompatibility can lead to potentially devastating outcomes.
SO.... The provider tests your blood early in the pregnancy and will reassure you if you have a positive Rh factor. If you have a negative Rh factor you will be given an injection of Rhogam ( gamma globulin ) that prevents the formation of or neutralizes the antibodies in the first place. No antibodies: NO PROBLEM. YOU THEN WILL NOT PRODUCE ANTIBODIES THAT COULD HURT YOUR BABY.
This injection is given routinely at twenty-eight weeks gestation and before you leave the hospital after the birth of your baby. It is important to notify your provider if you have had bleeding during this pregnancy and you'll simply get another injection for making sure that you cannot make antibodies. If you have amniocentesis or a miscarriage or a termination, you will be given an injection of Rhogam.
So that's why it's important that your blood is tested and that your health care providers know about your Rh factor. If your Rh factor is positive, it is never a problem, no matter what the Rh factor of the dad. If your Rh factor is negative, and your partner's Rh factor is also negative ( with documentation, not just word of mouth ) then you won't need Rhogam. But if you get the injection, it won't hurt you or the baby. YOU NEED RHOGAM IF YOUR Rh FACTOR IS NEGATIVE AND YOUR PARTNER'S IS POSITIVE. Especially if this is NOT your first pregnancy, whether you delivered or not. Be honest with your provider about your pregnancy history. And be grateful for those Rhogam injections.
IT IS ESSENTIAL THAT YOUR BLOOD BE TYPED, EARLY IN YOUR PREGNANCY. AND IF YOU HAVE A NEGATIVE Rh FACTOR, IT IS MOST IMPORTANT TO RECEIVE YOUR RHOGAM INJECTIONS.