Rh Incompatibility (Nursing)

00:00 Alright, our last bit of business today is to talk about Rh incompatibility. Yes, I know there are 2 types of the blood, there is the A, O, B, AB, and then there's the Rhesus. The reason we talk about Rh incompatibility because incompatibility between the blood type is usually very rare and insignificant in terms of causing complications. Rh incompatibility, however, can cause significant complications which is why we're going to talk about it. So, taking you back to a little bit of physiology and we think about antibodies that are produced.

00:34 If we have a patient who is Rh negative, they don't have antibodies in their system. If they become pregnant with a baby that is Rh positive and for some reason there is a mixing of the blood, now normally maternal blood and fetal blood don't mix so that's not the way that it's set up. But sometimes during testing, think about that CVS, think about that amniocentesis, think about someone who has experienced saying bleeding during the first trimester, there may be a little fetal blood that gets mixed in to that maternal system. And if that happens, the maternal bloodstream responds by producing antibodies. And the type of antibodies that are produced are called IgM antibodies. So that is a normal immunologic response to a foreign body. Now, IgM antibodies are really large, they're big and they can't cross over the the placenta. So, they will hang out in mom's bloodstream and that's completely fine and there won't be any problem with that fetus. So that fetus will be delivered and go on and do great things. Now, during a subsequent pregnancy, if there is another exposure of fetal and maternal blood, there is a memory going on. Right? So instead of IgM antibodies, IgG antibodies are produced. They are not big, they are small and yes they can cross over the placenta. And so when they cross over the placenta, they will actually attack the fetus and can lead to a myriad of complications. So, what do we do about it? We give a medication called Rhogam, and Rhogam is actually, for lack of a better way to explain, it's a pretend antibody. And it fools the body into thinking that it's made antibodies so it doesn't do it. And then these antibodies disappear after 14 weeks and it's like the whole thing never happen.

02:25 So, the mother never produces IgM antibodies that then turn into IgG antibodies and so during the next pregnancy it's like the first time all over again. Okay? So we give Rhogam at 28 weeks, we give Rhogam at delivery to make sure that the mother does not produce IgM antibodies. Okay? So, the reason why this is particularly important is that if you have a patient who is bleeding in the first trimester, we want to make sure that they get Rhogam.

02:56 Right? If you have a patient who is coming in at 28 weeks and you find out they're Rh negative, you want to make sure they get Rhogam. If you have a patient on the postpartum unit who is Rh negative after we've confirmed that the fetal blood type is positive, you want to make sure that they give Rhogam. So here are the things you want to remember one more time. Rhogam suppresses antibody formation in the maternal bloodstream. It's given at 28 weeks, it's given 72 hours after delivery after we confirm the blood type of the baby, and it's given before any invasive procedures like CVS and amniocentesis. Last little bit, remember, if we have any first trimester bleeding or spontaneous abortion and we have a patient who is Rh negative, we want to make sure that they also receive Rhogam. Sometimes this is forgotten and this sets up someone for sensitization which has big implications for subsequent pregnancies.