How do I know my Rh status and what does it mean? At your first prenatal visit, you will have a lab test to determine your blood type and your RH status. The Rh status tells us whether you have a particular protein on the surface of your red blood cells. This is kind of like a pirate flag to Rh negative blood cells. 90% of Caucasians are Rh+ and have this protein. This frequency varies somewhat with other ethnicities. However, if you are Rh negative and don’t have this protein, you will need to take special precautions during the course of your pregnancy.
Why is being Rh negative a problem when you are pregnant? If you are Rh negative, there is a high likelihood that your baby will be Rh positive. This is simply based on the fact that your partner is likely Rh positive (a pirate!). Essentially, this means that your blood and your baby’s blood will likely be incompatible. This incompatibility will not likely have any effect during your first pregnancy; however, if your baby’s blood leaks into your blood, which is a frequent occurrence during labor (and occasionally sooner if you have bleeding), your blood will develop antibodies against the Rh factor. Much like you would keep a lookout for pirates after you saw them the first time, these antibodies patrol and attack any proteins that they see in the future. This is called Rh sensitization. In a future pregnancy with an Rh positive baby, your blood can attack your baby’s blood.
What does it mean that my blood can attack my baby’s blood? Once your blood has developed antibodies against the Rh factor, it can attack your baby’s red blood cells and kill them. If this happens, it would essentially cause your baby to have anemia and can cause jaundice (yellowing of the skin), as well as more serious complications, such as brain damage, miscarriage or even stillbirth.
How do we prevent sensitization? If you are Rh negative, you will receive a shot called Rhogam during the time that your blood is most likely to be exposed to your baby’s blood (essentially, it provides a diversion for all of those pirate cells). This will prevent your body from developing antibodies and attacking your baby’s blood. Rhogam is administered at 28 weeks because it will protect you from antibody formation for 12 weeks (essentially up until delivery). Once you deliver, we will check the baby’s Rh status from a blood sample; if your baby is Rh positive then you will receive another dose of Rhogam to prevent any antibody formation that could have happened during bleeding from delivery.
Would I need Rhogam any other time during the course of my pregnancy if I am Rh negative? Most women only receive Rhogam at 28 weeks and after delivery if their baby is Rh positive. However, if you know that you are Rh negative and have had any of the following complications, you will likely need Rhogam to prevent sensitization: miscarriage, abortion, ectopic pregnancy, stillbirth, molar pregnancy, vaginal bleeding in early pregnancy, or abdominal injury during pregnancy.
Bottom Line: If you are pregnant, you need to know your Rh status! If you happen to be Rh negative, make sure that everyone that takes care of you while you are pregnant (especially urgent care or the ER) is aware so they do not forget to administer Rhogam to prevent your blood from becoming sensitized!Pam